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Anatomy at a Glance 



Omar Faiz 
David Moffat 



Blackwell Science 



Anatomy at a Glance 



OMAR FAIZ 

BSc(Hons),FRCS(Eng) 

Specialist Registrar in General Surgery 

DAVID MOFFAT 

VRD,MD,FRCS 

Emeritus Professor of Anatomy 

University of Cardiff 



Blackwell 

Science 



© 2002 by Blackwell Science Ltd 
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First published 2002 by Blackwell Science Ltd 
Reprinted 2002 

Library of Congress Cataloging-in-Publication Data 
Faiz, Omar. 

Anatomy at a glance / Omar Faiz, David Moffat 
p. cm. 

Includes index. 

ISBN 0-632-05934-6 (pbk.) 

1. Human anatomy — Outlines, syllabi, etc. I. Moffat, David, MD. II. Title. 

[DNLM:1: Anatomy. QS 4 F175a 2002] 

QM31.F33 2002 

611— dc21 2001052646 

ISBN 0-632-05934-6 

A Catalogue record for this title is available from the British Library. 

Set in 9/1 ly pt Times by Graphicraft Limited, Hong Kong 
Printed and bound in Italy by G. Canale & C. SpA, Turin 

For further information on 
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Contents 



Preface, 5 

The thorax 

1 The thoracic wall I, 6 

2 The thoracic wall II, 8 

3 The mediastinum I — the contents of the 
mediastinum, 10 

4 The mediastinum II — the vessels of the thorax, 12 

5 The pleura and airways, 14 

6 The lungs, 16 

7 The heart I, 18 

8 The heart II, 22 

9 The nerves of the thorax, 24 

10 Surface anatomy of the thorax, 26 

The abdomen and pelvis 

1 1 The abdominal wall, 28 

1 2 The arteries of the abdomen, 3 1 

1 3 The veins and lymphatics of the abdomen, 34 

14 The peritoneum, 36 

1 5 The upper gastrointestinal tract 1,38 

16 The upper gastrointestinal tract II, 40 

17 The lower gastrointestinal tract, 42 

18 The liver, gall-bladder and biliary tree, 44 

19 The pancreas and spleen, 46 

20 Theposterior abdominal wall, 48 

2 1 The nerves of the abdomen, 50 

22 Surface anatomy of the abdomen, 52 

23 The pelvis I — the bony and ligamentous pelvis, 54 

24 The pelvis II — the contents of the pelvis, 56 

25 The perineum, 58 

26 The pelvic viscera, 60 

The upper limb 

27 The osteology of the upper limb, 62 

28 Arteries of the upper limb, 66 

29 The venous and lymphatic drainage of the upper limb and the 
breast, 68 

30 Nerves of the upper limb I, 70 

31 Nerves of the upper limb II, 72 

32 The pectoral and scapular regions, 74 

33 The axilla, 76 

34 The shoulder (gleno-humeral) joint, 78 

35 The arm, 80 

36 The elbow joint and cubital fossa, 82 

37 The forearm, 84 

38 The carpal tunnel and joints of the wrist and hand, 86 



39 The hand, 88 

40 Surface anatomy of the upper limb. 



Theioweriimb 

The osteology of the lower limb, 92 

The arteries of the lower limb, 94 

The veins and lymphatics of the lower limb, 96 

The nerves of the lower limb I, 98 

The nerves of the lower limb II, 1 00 

The hip joint and gluteal region, 1 02 

47 The thigh, 106 

48 The knee joint and popliteal fossa, 1 09 
The leg, 112 
The ankle and foot I, 114 
The ankle and foot II, 116 
Surface anatomy of the lower limb, 118 



41 
42 
43 
44 
45 
46 



49 
50 
51 

52 



The autonomic nervous system 

53 The autonomic nervous system, 120 

The head and neci< 

54 The skull I, 122 

55 The skull II, 124 

56 Spinal nerves and cranial nerves I-IV, 126 

57 The trigeminal nerve (V), 128 

58 Cranial nerves VI-XII, 130 

59 The arteries I, 132 

60 The arteries II and the veins, 1 34 

6 1 Anterior and posterior triangles, 136 

62 The pharynx and larynx, 138 

63 The root of the neck, 140 

64 The oesophagus and trachea and the thyroid gland, 142 

65 The upper part of the neck and the submandibular 
region, 144 

66 The mouth, palate and nose, 146 

67 The face and scalp, 148 

68 The cranial cavity, 152 

69 The orbit and eyeball, 154 

70 The ear, and lymphatics and surface anatomy of the head and 
neck, 156 

The spine and spinai cord 

71 The spine, 158 

72 The spinal cord, 160 

Muscle index, 162 
Index, 168 



Contents 3 



Preface 



The study of anatomy has changed enormously in the last few decades. 
No longer do medical students have to spend long hours in the dissect- 
ing room searching fruitlessly for the otic ganglion or tracing the small 
arteries that form the anastomosis round the elbow joint. They now 
need to know only the basic essentials of anatomy with particular 
emphasis on their clinical relevance and this is a change that is long 
overdue. However, students still have examinations to pass and in this 
book the authors, a surgeon and an anatomist, have tried to provide a 
means of rapid revision without any frills. To this end, the book follows 
the standard format of the at a Glance series and is arranged in short, 
easily digested chapters, written largely in note form, with the appro- 
priate illustrations on the facing page. Where necessary, clinical appli- 
cations are included in italics and there are a number of clinical 
illustrations. We thus hope that this book will be helpful in revising and 
consolidating the knowledge that has been gained from the dissecting 
room and from more detailed and explanatory textbooks. 



The anatomical drawings are the work of Jane Fallows, with help 
from Roger Hulley, who has transformed our rough sketches into the 
finished pages of illustrations that form such an important part of the 
book and we should like to thank her for her patience and skill in carry- 
ing out this onerous task. Some of the drawings have been borrowed or 
adapted from Professor Harold Ellis's superb book Clinical Anatomy 
(9th edn) and we are most grateful to him for his permission to do this. 
We should also like to thank Dr Mike Benjamin of Cardiff University 
for the surface anatomy photographs. Finally, it is a pleasure to thank 
all the staff at Blackwell Science who have had a hand in the prepara- 
tion of this book, particularly Fiona Goodgame and Jonathan Rowley. 

Omar Faiz 
David Moffat 



Preface 5 



1 The thoracic wall I 




1 Costochondraljoint 

2 Sternocostaljoint 

3 Interchondraljoint 

4 Xiphisternaljoint 

5 Manubriosternaljoint 
(angle of Louis) 

Fig.1.1 

The thoracic cage. The outlet (inlet) 
of the thorax is outlined 



Head 



Facet for 
vertebral body 



Tubercle 




Angle 



Fig.1.2 

A typical rib 



Subcostal groove 



Thoracic outlet (inlet) 

First rib 

Clavicle 

Suprasternal notch 

Manubrium 

Third rib 

Body of sternum 



Intercostal 
space 

Xiphisternum 



Floating ribs 



Costovertebral 
joint 

Costotransverse 
joint 



Scalenus 
anterior 



E3rachial 
Costal cartilage plexus 

Costal margin 




Cervical 
rib 



Subclavian 
artery 

Fig.1.3 

Bilateral cervical ribs. 
On the right side the brachial plexus 
is shown arching o'^er the rib and 
stretching its lowest trunk 



Transverse process with 
facet for rib tubercle 



Demifacet for head of rib 




6th 
rib 



Fig.1.4 

Joints of the thoracic cage 



Costochondral ■ 
joint 



6 Thorax 



The thoracic cage 

The thoracic cage is formed by the sternum and costal cartilages in 
front, the vertebral column behind and the ribs and intercostal spaces 
laterally. 

It is separated from the abdominal cavity by the diaphragm and com- 
municates superiorly with the root of the neck through the thoracic 
inlet (Fig. 1.1). 

The ribs (Fig. i.i) 

• Of the 1 2 pairs of ribs the first seven articulate with the vertebrae pos- 
teriorly and with the sternum anteriorly by way of the costal cartilages 
(true ribs). 

• The cartilages of the 8th, 9th and 10th ribs articulate with the carti- 
lages of the ribs above (false ribs). 

• The 1 1th and 12th ribs are termed 'floating' because they do not articu- 
late anteriorly (false ribs). 

Typical ribs (3rd-9th) 

These comprise the following features (Fig. 1.2): 

• A head which bears two demifacets for articulation with the bodies 
of: the numerically corresponding vertebra, and the vertebra above 
(Fig. 1.4). 

• A tubercle which comprises a rough non-articulating lateral facet as 
well as a smooth medial facet. The latter articulates with the transverse 
process of the corresponding vertebra (Fig . 1.4). 

• A subcostal groove: the hollow on the inferior inner aspect of the 
shaft which accommodates the intercostal neurovascular structures. 

Atypical ribs (1st, 2nd, 10th, 11th, 12th) 

• The 1st rib (see Fig. 63.2) is short, flat and sharply curved. The head 
bears a single facet for articulation. A prominent tubercle (scalene 
tubercle) on the inner border of the upper surface represents the inser- 
tion site for scalenus anterior. The subclavian vein passes over the 1st 
rib anterior to this tubercle whereas the subclavian artery and lowest 
trunk of the brachial plexus pass posteriorly. 

A cervical lib is a rare 'extra' rib which articulates with C7 poster- 
iorly and the 1st rib anteriorly. A neurological deficit as well as vascu- 
lar insufficiency arise as a result of pressure from the rib on the lowest 
trunk of the brachial plexus (Tl) and subclavian artery, respectively 
(Fig. 1.3). 



• The 2nd rib is less curved and longer than the Istrib. 

• The 10th rib has only one articular facet on the head. 

• The 11th and 12th ribs are short and do not articulate anteriorly. 
They articulate posteriorly with the vertebrae by way of a single facet 
on the head. They are devoid of both a tubercle and a subcostal groove. 

The sternum (Fig. i.i) 

The sternum comprises a manubrium, body and xiphoid process. 

• The manubrium has facets for articulation with the clavicles, 1st 
costal cartilage and upper part of the 2nd costal cartilage. It articulates 
inferiorly with the body of the sternum at the manubriosternal joint. 

• The body is composed of four parts or sternebrae which fuse between 
15 and 25 years of age. It has facets for articulation with the lower part 
of the 2nd and the 3rd to 7th costal cartilages. 

• The xiphoid articulates above with the body at the xiphisternal joint. 
The xiphoid usually remains cartilaginous well into adult life. 

Costal cartilages 

These are bars of hyaline cartilage which connect the upper seven ribs 
directly to the sternum and the 8th, 9 th and 10th ribs to the cartilage 
immediately above. 

Joints of the thoracic cage (Figs i.i and 1.4) 

• The manubriosternal joint is a symphysis. It usually ossifies after the 
age of 30. 

• The xiphisternal joint is also a symphysis. 

• The 1st sternocostal joint is a primary cartilaginous joint. The rest 
(2nd to 7th) are synovial joints. All have a single synovial joint except 
for the 2nd which is double. 

• The costochondrat joints (between ribs and costal cartilages) are prim- 
ary cartilaginous joints. 

• The interchondral joints (between the costal cartilages of the 8th, 9th 
and 10th ribs) are synovial joints. 

• The costovertebral joints comprise two synovial joints formed by the 
articulations of the demifacets on the head of each rib with the bodies of 
its corresponding vertebra together with that of the vertebra above. The 
1st and 10th-12th ribs have a single synovial joint with their corres- 
ponding vertebral bodies. 

• The costotransverse joints are synovial joints formed by the articula- 
tions between the facets on the rib tubercle and the transverse process 
of its corresponding vertebra. 



The thoracic wall I 7 



2 The thoracic wall II 




Fig.2.1 

An intercostal space 



Vein 

Artery 

Nerve 



Intercostal 



External 

Internal 

Innermost 



Intercostal muscles 



Posterior ramus 



Collateral branch 
(to muscles) 

lateral 



Cutaneous 
branches 

Fig.2.2 

The vessels and nerves 
of an intercostal space 




Posterior 

intercostal 

artery 



Anterior 

intercostal 

artery 



Vertebral 
levels 



T10 




T12 



Fig.2.3 

The diaphragm 



Xiphisternum 

Costal margin 
Central tendon 
Inferior vena cava 

Oesophagus 

Aorta 

Lateral arcuate ligament 
Medial arcuate ligament 
Right crus 

Psoas major 
Quadratus lumborum 

Third lumbar vertebra 



8 Thorax 



The intercostal space (Fig. 2.1) 

Typically, each space contains three muscles comparable to those of 
the abdominal wall. These include the: 

• External intercostal: this muscle fills the intercostal space from the 
vertebra posteriorly to the costochondral junction anteriorly where it 
becomes the thin anterior intercostal membrane. The fibres run down- 
wards and forwards from rib above to rib below. 

• Internal intercostal: this muscle fills the intercostal space from the 
sternum anteriorly to the angles of the ribs posteriorly where it becomes 
the posterior intercostal membrane which reaches as far back as the 
vertebral bodies. The fibres run downwards and backwards. 

• Innermost intercostals: this group comprises the subcostal muscles 
posteriorly, the intercostales intimi laterally and the transversus thor- 
acis anteriorly. The fibres of these muscles span more than one inter- 
costal space. 

The neurovascular space is the plane in which the neurovascular 
bundle (intercostal vein, artery and nerve) courses. It lies between the 
internal intercostal and innermost intercostal muscle layers. 

The intercostal structures course under cover of the subcostal 
groove. Pleural aspiration should be performed close to the upper bor- 
der of a rib to minimize the risk of injury. 

Vascular supply and venous drainage of the chest wall 

The intercostal spaces receive their arterial supply from the anterior 
and posterior intercostal arteries. 

• The anterior intercostal arteries are branches of the internal thoracic 
artery and its terminal branch the musculophrenic artery. The lowest 
two spaces have no anterior intercostal supply (Fig. 2.2). 

• The first 2-3 posterior intercostal arteries arise from the superior 
intercostal branch of the costocervical trunk, a branch of the 2nd part of 
the subclavian artery (see Fig. 60.1). The lower nine posterior inter- 
costal arteries are branches of the thoracic aorta. The posterior inter- 
costal arteries are much longer than the anterior intercostal arteries 
(Fig. 2.2). 

The anterior intercostal veins drain anteriorly into the internal thor- 
acic and musculophrenic veins. The posterior intercostal veins drain 
into the azygos and hemiazygos systems (see Fig. 4.2). 

Lymphatic drainage of the chest wall 

Lymph drainage from the: 

• Anterior chest wall: is to the anterior axillary nodes. 

• Posterior chest wall: is to the posterior axillary nodes. 

• Anterior intercostal spaces: is to the internal thoracic nodes. 

• Posterior intercostal spaces: is to the para-aortic nodes. 

Nervesupply of the chest wall (Fig. 2.2) 

The intercostal nerves are the anterior primary rami of the thoracic seg- 
mental nerves. Only the upper six intercostal nerves run in their inter- 
costal spaces, the remainder gaining access to the anterior abdominal 
wall. 

Branches of the intercostal nerves include: 

• Cutaneous anterior and lateral branches. 



• A collateral branch which supplies the muscles of the intercostal 
space (also supplied by the main intercostal nerve). 

• Sensory branches from the pleura (upper nerves) and peritoneum 
(lower nerves). 

Exceptions include: 

• The 1st intercostal nerve is joined to the brachial plexus and has no 
anterior cutaneous branch. 

• The 2nd intercostal nerve is joined to the medial cutaneous nerve of 
the arm by the intercostobrachial nerve branch. The 2nd intercostal 
nerve consequently supplies the skin of the armpit and medial side of 
the arm. 

The diaphragm (Fig. 2.3) 

The diaphragm separates the thoracic and abdominal cavities. It is com- 
posed of a peripheral muscular portion which inserts into a central 
aponeurosis — the central tendon. 

The muscular part has three component origins: 

• A vertebral part: this comprises the crura and arcuate ligaments. 
The right crus arises from the front of the Ll-3 vertebral bodies and 

intervening discs. Some fibres from the right crus pass around the lower 
oesophagus. 

The left crus originates from LI and L2 only. 

The medial arcuate ligament is made up of thickened fascia which 
overlies psoas major and is attached medially to the body of LI and lat- 
erally to the transverse process of LI. The lateral arcuate ligament is 
made up of fascia which overlies quadratus lumborum from the trans- 
verse process of LI medially to the 12th rib laterally. 

The median arcuate ligament is a fibrous arch which connects left 
and right crura. 

• h costal part: attached to the inner aspects of the lower six ribs. 

• A sternal part: consists of two small slips arising from the deep sur- 
face of the xiphoid process. 

Openings in the diaphragm 

Structures traverse the diaphragm at different levels to pass from 
thoracic to abdominal cavities and vice versa. These levels are as 
follows: 

• T8, \he. opening for the inferior vena cava: transmits the inferior vena 
cava and right phrenic nerve. 

• TIO, the oesophageal opening: transmits the oesophagus, vagi and 
branches of the left gastric artery and vein. 

• T12, the aortic opening: transmits the aorta, thoracic duct and azygos 
vein. 

The left phrenic nerve passes into the diaphragm as a solitary 
structure. 

Nerve supply of the diaphragm 

• Motor supply: the entire motor supply arises from the phrenic nerves 
(C3,4,5). Diaphragmatic contraction is the mainstay of inspiration. 

• Sensory supply: the periphery of the diaphragm receives sensory 
fibres from the lower intercostal nerves. The sensory supply from the 
central part is carried by the phrenic nerves. 



The thoracic wall II 9 



3 The mediastinum I— tiie contents of tlie mediastinum 



Superior mediastinum 



Great \/essels 

Tracliea 
Oesophagus 
Tliymus, etc. 



Anterior mediastinum 



Tliymus 



Fig.3.1 

Tlie subdivisions of tlie mediasti 
and their principal contents 




Middle mediastinum 

Heart and roots of great vessels 

Pericardium 



Posterior mediastinum 



Oesophagus 

Descending thoracic aorta 

Thoracic duct 

Azygos and hemiazygos veins 

Sympathetic trunk, etc. 



Right 
vag 




crus 



Left crus 



Oesophagus 
Trachea 
Recurrent 
laryngeal nerve 

Thoracic duct 
Left vagus 

Anterior 

pulmonary 

plexus 

Oesophageal 
plexus 

Anterior 
vagal trunk 

Oesophageal 
opening (T10) 

Aortic opening 
(T12) 



Fig.3.2 

The course and principal relations of the oesophagus. 
Note that it passes through the right crus of the 
diaphragm 




Jugular lymph trunks 

Right lymph duct 

Thoracic duct 

Subclavian lymph trunk 

EJronchomediastinal 
lymph trunk 

Superior vena cava 
From chest wall (right) 

From chest wall (left) 

Diaphragm 

Cisterna chyli 

From kidneys and 
abdominal wall 

From abdominal 
viscera 

From lower limbs 



Fig.3.3 

The thoracic duct and its areas of drainage. 
The right lymph duct is also shown 



10 Thorax 



Subdivisions of tlie mediastinum (Fig. 3.1) 

The mediastinum is tiie space located between tlie two pleural sacs. For 
descriptive purposes it is divided into superior and inferior mediastinal 
regions by a line drawn backwards horizontally from the angle of Louis 
(manubriosternal joint) to the vertebral column (T4/5 intervertebral disc). 

The superior mediastinum communicates with the root of the neck 
through the 'thoracic inlet'. The latter opening is bounded anteriorly by 
the manubrium, posteriorly by Tl vertebra and laterally by the 1st rib. 

The inferior mediastinum is further subdivided into the: 

• Anterior mediastinum: the region in front of the pericardium. 

• Middle mediastinum: consists of the pericardium and heart. 

• Posterior mediastinum: the region between the pericardium and 
vertebrae. 

Tlie contents of tlie mediastinum (Figs 3.1 and 3.2) 

The oesophagus 

• Course: the oesophagus commences as a cervical structure at the 
level of the cricoid cartilage at C6 in the neck. In the thorax the oesoph- 
agus passes initially through the superior and then the posterior medi- 
astina. Having deviated slightly to the left in the neck the oesophagus 
returns to the midline in the thorax at the level of T5. From here, it 
passes downwards and forwards to reach the oesophageal opening in 
the diaphragm (TIO). 

• Structure: the oesophagus is composed of four layers: 

• An inner mucosa of stratified squamous epithelium. 

• A submucous layer. 

• A double muscular layer — longitudinal outer layer and circular 
inner layer. The muscle is striated in the upper two-thirds and 
smooth in the lower third. 

• An outer layer of areolar tissue. 

• Relations: the relations of the oesophagus are shown in Fig. 3.2. On 
the right side the oesophagus is crossed only by the azygos vein and the 
right vagus nerve and hence this forms the least hazardous surgical 
approach. 

• Arterial supply and venous drainage: owing to the length of this 
structure (25 cm), the oesophagus receives arterial blood from varied 
sources throughout its course: 

• Upper third — inferior thyroid artery. 

• Middle third — oesophageal branches of thoracic aorta. 

• Lower third — left gastric branch of coeliac artery. 



Similarly the venous drainage varies throughout its length: 

• Upper third — inferior thyroid veins. 

• Middle third — azygos system. 

• Lower third — both the azygos (systemic system) and left gastric 
veins (portal system). 

The dual drainage of the lower third forms a site of portal-systemic 
anastomosis. In advanced liver cirrhosis, portal pressure rises result- 
ing in back-pressure on the left gastric tributaries at the lower oesoph- 
agus. These veins become distended and fragile (oesophageal varices). 
They are predisposed to rupture, causing potentially life-threatening 
haemorrhage . 

• Lymphatic drainage: this is to a peri-oesophageal lymph plexus and 
then to the posterior mediastinal nodes. From here lymph drains into 
supraclavicular nodes. The lower oesophagus also drains into the nodes 
around the left gastric vessels. 

Carcinoma of the oesophagus carries an extremely poor prognosis. 
Two main histological types — squamous and adenocarcinoma — 
account for the majority of tumours. The incidence of adenocarcinoma of 
the lower third of the oesophagus is currently increasing for unknown 
reasons. Most tumours are unresectable at the time of diagnosis. The 
insertion of stents and use of lasers to pass through tumour obstruction 
have become the principal methods of palliation. 

The thoracic duct (Fig. 3.3) 

• The cisterna chyli is a lymphatic sac that receives lymph from the 
abdomen and lower half of the body. It is situated between the abdom- 
inal aorta and the right crus of the diaphragm. 

• The thoracic duct carries lymph from the cisterna chyli through the 
thorax to drain into the left brachiocephalic vein. It usually receives 
tributaries from the left jugular, subclavian and mediastinal lymph 
trunks, although they may open into the large neck veins directly. 

• On the right side the main lymph trunks from the right upper body 
usually join and drain directly through a common tributary, the right 
lymph duct, into the right brachiocephalic vein. 

The thymus gland 

• This is an important component of the lymphatic system. It usually 
lies behind the manubrium (in the superior mediastinum) but can 
extend to about the 4th costal cartilage in the anterior mediastinum. 
After puberty the thymus is gradually replaced by fat. 



The mediastinum I— the contents of the mediastinum 1 1 



^ The mediastinum II— tlie vessels of the thorax 



Inferior thyroid 

Superficial cervical 

Suprascapulai 

Thyrocervical trunk 
Vertebral 



Inferior laryngeal 



Scalenus anterior 
Dorsal scapular - 
Subclavian 



Internal thoracic (mammary) 

Anterior intercostals 

Musculophrenic 

Superior epigastric 



Subcostal 



Fig.4.1 




The branches of the arch and the descending thoracic aorta 



Thyroidea ima 

Costocervical trunk 

Deep cervical 

Superior intercostal 
Upper two posterior 
intercostals 

EJrachiocephalic 



Posterior intercostals 
(also supply_spinal cord) 
bronchial 

Oesophageal branches 
Mediastinal 



Aortic opening in diaphragm 
(T12) 



Left brachiocephalic 

Right lymph duct ^=rJ 

Right brachiocephalic 

Superior vena cava 

Right atrium 
Azygos 




Diaphragm 



Fig.4.2 

The principal veinsof the thorax 



Inferior thyroid 
Left internaljugular 

Thoracic duct 

Vertebral 
Left subclavian 
Internal thoracic 
Left superior intercostal 



Vagus nerve 
Phrenic nerve 



Crossing arch 
of the aorta 



Posterior intercostal 
Accessory hemiazygos 



Hemiazygos 



Aortic opening in diaphragm 



12 Thorax 



The thoracic aorta (Fig. 4.1) 

The ascending aorta arises from thie aortic vestibule behind the 
infundibulum of the right ventricle and the pulmonary trunk. It is con- 
tinuous with the aortic arch. The arch lies posterior to the lower half of 
the manubrium and arches from front to back over the left main 
bronchus. The descending thoracic aorta is continuous with the arch 
and begins at the lower border of the body of T4. It initially lies slightly 
to the left of the midline and then passes medially to gain access to the 
abdomen by passing beneath the median arcuate ligament of the 
diaphragm at the level of T12. From here it continues as the abdominal 
aorta. 

The branches of the ascending aorta are the: 

• Right and left coronary arteries. 

The branches of the aortic arch are the: 

• Brachiocephalic artery: arises from the arch behind the manubrium 
and courses upwards to bifurcate into right subclavian and right com- 
mon carotid branches posterior to the right sternoclavicular joint. 

• Left common carotid artery: seep. 133. 

• Left subclavian artery. 

• Thyroidea ima artery. 

The branches of the descending thoracic aorta include the: 

• Oesophageal, bronchial, mediastinal, posterior intercostal and sub- 
costal arteries. 

The subclavian arteries (see Fig. eo.i) 

The subclavian arteries become the axillary arteries at the outer bor- 
der of the 1st rib. Each artery is divided into three parts by scalenus 
anterior: 

• 1st part: the part of the artery that lies medial to the medial border of 
scalenus anterior. It gives rise to three branches, the: vertebral artery 
(p. 135), thyrocervical trunk and internal thoracic (mammary) artery. 
The latter artery courses on the posterior surface of the anterior chest 
wall one flngerbreadth from the lateral border of the sternum. Along 
its course it gives off anterior intercostal, thymic and perforating 
branches. The 'perforators' pass through the anterior chest wall to 



supply the breast. The internal thoracic artery divides behind the 6th 
costal cartilage into superior epigastric and musculophrenic branches. 
The thyrocervical trunk terminates as the inferior thyroid artery. 

• 2nd part: the part of the artery that lies behind scalenus anterior. It 
gives rise to the costocervical trunk (see Fig. 60. 1). 

• 3rd part: the part of the artery that lies lateral to the lateral border of 
scalenus anterior. This part gives rise to the dorsal scapular artery. 

The great veins (Fig. 4.2) 

The brachiocephalic veins are formed by the confluence of the subcla- 
vian and internal jugular veins behind the sternoclavicular joints. The 
left brachiocephalic vein traverses diagonally behind the manubrium to 
join the right brachiocephalic vein behind the 1st costal cartilage thus 
forming the superior vena cava. The superior vena cava receives only 
one tributary — the azygos vein. 

The azygos system of veins (Fig. 4.2) 

• The azygos vein: commences as the union of the right subcostal vein 
and one or more veins from the abdomen. It passes through the aortic 
opening in the diaphragm, ascends on the posterior chest wall to the 
level of T4 and then arches over the right lung root to enter the superior 
vena cava. It receives tributaries from the: lower eight posterior inter- 
costal veins, right superior intercostal vein and hemiazygos veins. 

• The hemiazygos vein: arises on the left side in the same manner as the 
azygos vein. It passes through the aortic opening in the diaphragm and 
up to the level of T9 from where it passes diagonally behind the aorta 
and thoracic duct to drain into the azygos vein at the level of T8. It 
receives venous blood from the lower four left posterior intercostal 
veins. 

• The accessory hemiazygos vein: drains blood from the middle poster- 
ior intercostal veins (as well as some bronchial and mid-oesophageal 
veins). The accessory hemiazygos crosses to the right to drain into the 
azygos vein at the level of T7. 

• The upper four left intercostal veins drain into the left brachio- 
cephalic vein via the left superior intercostal vein. 



The mediastinum II — the vessels of the thorax 1 3 



5 The pleura and airways 





Pulmonary artery 
Bronchus 
Pulmonary veins 
Lymph node 
Cut edge of pleura 
Pulmonary ligament 



Fig. 5.1 

The principal structures 
in the hilum of the lung 



Cricoid {C6) 



Trachea 



Right main bronchus 



Apical — 
Posterior 
Anterior / 

Middle 

Anterior basal 

Lateral basal 
Posterior basal 

Fig. 5.2 

The trachea and main bronchi 



Brachiocephalic 
artery 

Superior — 
vena cava 





Thyroid 

isthmus 

Left 
brachiocephalic 



Aortic arch 



pulmonary 
artery 

Fig. 5.3 

The anterior relations of the trachea 



Left main bronchus 



Apical 
Posterior 
Apico-posterior 
Anterior 



Lingular 



Anterior basal 
Lateral basal 
Posterior basal 



14 Thorax 



The respiratory tract is most often discussed in terms of upper and 
lower parts. The upper respiratory tract relates to the nasopharynx and 
larynx whereas the lower relates to the trachea, bronchi and lungs. 

The pleurae 

• Each pleura consists of two layers: a visceral layer which is adherent 
to the lung and si parietal layer which lines the inner aspect of the chest 
wall, diaphragm and sides of the pericardium and mediastinum. 

• At the hilum of the lung the visceral and parietal layers become con- 
tinuous. This cuff hangs loosely over the hilum and is known as \he, pul- 
monary ligament. It permits expansion of the pulmonary veins and 
movement of hilar structures during respiration (Fig. 5.1). 

• The two pleural cavities do not connect. 

• The pleural cavity contains a small amount of pleural fluid which acts 
as a lubricant decreasing friction between the pleurae. 

• During maximal inspiration the lungs almost fill the pleural cavities. 
In quiet inspiration the lungs do not expand fully into the costo- 
diaphragmatic and costomediastinal recesses of the pleural cavity. 

• The parietal pleura is sensitive to pain and touch (carried by the inter- 
costal and phrenic nerves). The visceral pleura is sensitive only to 
stretch (carried by autonomic afferents from the pulmonary plexus). 

Air can enter the pleural cavity following a fractured rib or a torn 
lung (pneumothorax). This eliminates the normal negative pleural 
pressure, causing the lung to collapse. 

Inflammation of the pleura (pleurisy) results from infection of the 
adjacent lung (pneumonia). When this occurs the inflammatory process 
renders the pleura sticky. Under these circumstances a pleural rub can 
often be auscultated over the affected region during inspiration and 
expiration. Pus in the pleural cavity (secondary to an infective process) 
is termed an empyema. 

The trachea (Fig. 5.2) 

• Course: the trachea commences at the level of the cricoid cartilage in 
the neck (C6). It terminates at the level of the angle of Louis (T4/5) 
where it bifurcates into right and left main bronchi. 



• Structure: the trachea is a rigid fibroelastic structure. Incom- 
plete rings of hyaline cartilage continuously maintain the patency of 
the lumen. The trachea is lined internally with ciliated columnar 
epithelium. 

• Relations: behind the trachea lies the oesophagus. The 2nd, 3rd and 
4th tracheal rings are crossed anteriorly by the thyroid isthmus (Figs 5.3 
and 64.1). 

• Blood supply: the trachea receives its blood supply from branches of 
the inferior thyroid and bronchial arteries. 

The bronchi and bronchopulmonary segments (Fig. 5.2) 

• The right main bronchus is shorter, wider and takes a more vertical 
course than the left. The width and vertical course of the right main 
bronchus account for the tendency for inhaled foreign bodies to prefer- 
entially impact in the right middle and lower lobe bronchi. 

• The left main bronchus enters the hilum and divides into a superior 
and inferior lobar bronchus. The right main bronchus gives off the 
bronchus to the upper lobe prior to entering the hilum and once into the 
hilum divides into middle and inferior lobar bronchi. 

• Each lobar bronchus divides within the lobe into segmental bronchi. 
Each segmental bronchus enters a bronchopulmonary segment. 

• Each bronchopulmonary segment is pyramidal in shape with its apex 
directed towards the hilum (see Fig. 6.1). It is a structural unit of a lobe 
that has its own segmental bronchus, artery and lymphatics. If one 
bronchopulmonary segment is diseased it may be resected with pre- 
servation of the rest of the lobe. The veins draining each segment are 
intersegmental. 

Bronchial carcinoma is the commonest cancer among men in the 
United Kingdom. Four main histological types occur of which small 
cell carries the worst prognosis. The overall prognosis remains 
appalling with only 10% of sufferers surviving 5 years. It occurs most 
commonly in the mucous membranes lining the major bronchi near the 
hilum. Local invasion and spread to hilar and tracheobronchial nodes 
occurs early. 



The pleura and airways 15 



6 The lungs 




LEFT LUNG 





RIGHT LUNG 



1 

2 


Apical 

Posterior (1 and 2 from a common apico-posterior stem on tlie left side) 


3 


Anterior 


4and5 


Lateral and medial middle lobe (superior and inferior lingular on leftside) 


6 
7 


Superior (apical) 

Medial basal (cardiac on left) 


d 


Anterior basal (7 and 5 often by a common stem on left) 


9 


Lateral basal 


10 


Posterior basal 




I I Upper lobe 
I I Middle lobe 
I I Lower lobe 

Fig. 6.1 

The segmental bronchi (viewed from 
the lateral side) and the broncho- 
pulmonary segments, with their 
standard numbering 



Right atrium 
Diaphragm 
Breast shadow 

Fig. 6.2 

P-A. Chest X-ray 




Trachea 

Arch of aorta 

Lung hilum 
Left ventricle 

Costophrenic angle 



16 Thorax 



The lungs (Fig. 6.1) 

• The lungs provide an alveolar surface area of approximately 40 m" 
for gaseous exchange. 

• Each lung has : an apex which reaches above the sternal end of the 1 st 
rib; a costovertebral surface which underlies the chest wall; a base 
overlying the diaphragm and a mediastinal surface which is moulded to 
adjacent mediastinal structures. 

• Structure: the right lung is divided into upper, middle and lower 
lobes by oblique and horizontal fissures. The left lung has only an 
oblique fissure and hence no middle lobe. The lingular segment repres- 
ents the left sided equivalent of the right middle lobe. It is, however, an 
anatomical part of the left upper lobe. 

Structures enter or leave the lungs by way of the lung hilum which, 
as mentioned earlier, is ensheathed in a loose pleural cuff (see Fig. 5.1). 

• Blood supply: the bronchi and parenchymal tissue of the lungs are 
supplied by bronchial arteries — branches of the descending thoracic 
aorta. Bronchial veins, which also communicate with pulmonary veins, 
drain into the azygos and hemiazygos. The alveoli receive deoxy- 
genated blood from terminal branches of the pulmonary artery and oxy- 
genated blood returns via tributaries of the pulmonary veins. Two 
pulmonary veins return blood from each lung to the left atrium. 

• Lymphatic drainage of the lungs: lymph returns from the periphery 
towards the hilar tracheobronchial groups of nodes and from here to 
mediastinal lymph trunks. 

• Nerve supply of the lungs: a pulmonary plexus is located at the root 
of each lung. The plexus is composed of sympathetic fibres (from the 
sympathetic trunk) and parasympathetic fibres (from the vagus). 
Efferent fibres from the plexus supply the bronchial musculature and 
afferents are received from the mucous membranes of bronchioles and 
from the alveoli. 

The mechanics of respiration 

• A negative intrapleural pressure keeps the lungs continuously par- 
tially inflated. 



• During normal inspiration: contraction of the upper external inter- 
costals increases the A-P diameter of the upper thorax; contraction of 
the lower external intercostals increases the transverse diameter of the 
lower thorax; and contraction of the diaphragm increases the vertical 
length of the internal thorax. These changes serve to increase lung vol- 
ume and thereby result in reduction of intrapulmonary pressure causing 
air to be sucked into the lungs. In deep inspiration the sternocleidomas- 
toid, scalenus anterior and medius, serratus anterior and pectoralis 
major and minor all aid to maximize thoracic capacity. The latter are 
termed collectively — the accessory muscles of respiration. 

• Expiration is mostly due to passive relaxation of the muscles of inspira- 
tion and elastic recoil of the lungs. In forced expiration the abdominal 
musculature aids ascent of the diaphragm. 

The chest X-ray (CXR) (Fig. 6.2) 

The standard CXR is the postero-anterior (PA) view. This is taken with 
the subject's chest touching the cassette holder and the X-ray beam 
directed anteriorly from behind. 

Structures visible on the chest X-ray include the: 

• Heart borders: any significant enlargement of a particular chamber 
can be seen on the X-ray. In congestive cardiac failure all four cham- 
bers of the heart are enlarged (cardiomegaly). This is identified on the 
PA view as a cardiothoracic ratio greater than 0.5. This ratio is calcu- 
lated by dividing the width of the heart by the width of the thoracic cav- 
ity at its widest point. 

• Lungs: the lungs are radiolucent. Dense streaky shadows, seen at the 
lung roots, represent the blood-filled pulmonary vasculature. 

• Diaphragm : the angle made between the diaphragm and chest wall is 
termed the costophrenic angle. This angle is lost when a pleural effu- 
sion collects. 

• Mediastinal structures: these are difficult to distinguish as there is 
considerable overlap. Clearly visible, however, is the aortic arch 
which, when pathologically dilated (aneurysmal), creates the impres- 
sion of 'widening' of the mediastinum. 



The limgs 1 7 



7 The heart I 



Right recurrent laryngeal 



Right vagus ■ 



Right phrenic 

Brachiocephalic artery 



Right - 



brachiocephalic vein 
Right recurrent laryngeal 
Superior vena cava 



Right pulmonary veins 



Right atrium 



Inferior vena cava 

Fig.7.1 

The heart and the great vessels 




Thyroid 

Left phrenic 

Left vagus 

Left common carotid artery 

Inferior thyroid veins 
Left subclavian artery 
Left brachiocephalic vein 

Left pulmonary artery 
Left recurrent laryngeal 
Left bronchus 
Left pulmonary veins 




Pericardium 



M 



Heart 




Pulmonary trunk 

Aorta 

Arrow in transverse sinus 

Pulmonary veins 

Back of left atrium 
Back of right atrium 
Inferior vena cava 
Parietal pericardium 
Visceral pericardium 
Arrow in oblique sinus 



Fig.7.2 

The sinuses of the pericardium. The heart has been removed from the pericardial cavity and turned over to show its 
posterior aspect. The red line shows the cut edges where the visceral pericardium is continuous with the parietal pericardium. 
Visceral layer: blue, parietal layer: red 



18 Thorax 



The heart, pericardium, lung roots and adjoining parts of the great ves- 
sels constitute the middle mediastinum (Figs 3.1 and 7.1). 

The pericardium 

The pericardium comprises fibrous and serous components. The 
fibrous pericardium is a strong layer which covers the heart. It fuses 
with the roots of the great vessels above and with the central tendon of 
the diaphragm below. The serous pericardium lines the fibrous peri- 
cardium (parietal layer) and is reflected at the vessel roots to cover the 
heart surface (visceral layer). The serous pericardium provides smooth 
surfaces for the heart to move against. Two important sinuses are 
located between the parietal and visceral layers. These are the: 

• Transverse sinus — located between the superior vena cava and left 
atrium posteriorly and the pulmonary trunk and aorta anteriorly 
(Fig. 7.2). 

• Oblique sinus — behind the left atrium, the sinus is bounded by the 
inferior vena cava and the pulmonary veins (Fig. 7.2). 



• Blood supply: from the pericardiacophrenic branches of the internal 
thoracic arteries. 

• Nerve supply: the fibrous pericardium and the parietal layer of 
serous pericardium are supplied by the phrenic nerve. 

Following thoracic trauma blood can collect in the pericardial 
space (haemopericardium) which may, in turn, lead to cardiac tam- 
ponade. This manifests itself clinically as shock, distended neck veins 
and muffled I absent heart sounds (Beck's triad). This condition is fatal 
unless pericardial decompression is effected immediately. 

Tlie tieart surfaces 

• The anterior {sternocostal) surface comprises the: right atrium, atri- 
oventricular groove, right ventricle, a small strip of left ventricle and 
the auricle of the left atrium. 

• The inferior (diaphragmatic) surface comprises the: right atrium, 
atrioventricular groove and both ventricles separated by the interven- 
tricular groove. 

• The posterior surface {base) comprises the left atrium receiving the 
four pulmonary veins. 



The heart I 19 



Superior vena cava 

Portion of rig lit 
atrium derived 
from sinus 
venosus 

Musculi 
pectinati 

Crista 
terminalis 

Inferior 
vena cava 




Fig.7.3 

The interior of the right atrium 



Valve of the inferior 
vena cava 



Fig.7.4 

The interior of the left atrium and ventricle. 
The arrow shows the direction of blood flow. 
Note that blood flows o\/ev both surfaces 
of the anterior cusp of the mitral valve 



Limbus 
fossa ovalis 
Fossa ovalis 

Opening of 
coronary sinus 

Valve of the 
coronary sinus 




Right atrium 
Left atrium 



Mitral 
valve 



Fig.7.5 

A section through the heart at the level of the valves. 
The aortic and pulmonary valves are closed and the 
mitral and tricuspid valves open, as they would be 
during ventricular diastole 




Pulmonary valve 
(posterior, anterolateral 
and anteromedial cusps) 

Opening of right coronary artery 

Aortic valve 

(Anterior (right coronary) cusp. 
Left posterior (left coronary) cusp, 
right posterior (non-coronary) cusp) 



Anterior 

cusp Septal 
Posterior cusp 
cusp 



Tricuspid valve 
Anterior 



cusp 
Posterior 



cusp 



20 Thorax 



The heart chambers 

The right atrium (Fig. 7.3) 

• Receives deoxygenated blood from the inferior vena cava below and 
from the superior vena cava above. 

• Receives the coronary sinus in its lower part (p. 23). 

• The upper end of the atrium projects to the left of the superior vena 
cava as the right auricle. 

• The sulcus terminalis is a vertical groove on the outer surface of the 
atrium. This groove corresponds internally to the crista terminalis — a 
muscular ridge which separates the smooth walled atrium (derived 
from the sinus venosus) from the rest of the atrium (derived from the 
true fetal atrium). The latter contains horizontal ridges of muscle — 
musculi pectinati. 

• Above the coronary sinus the interatrial septum forms the posterior 
wall. The depression in the septum — Xhe. fossa oralis — represents the 
site of the foramen ovale. Its floor is the fetal septum primum. The 
upper ridge of the fossa ovalis is termed the limbus, which represents 
the septum secundum. Failure of fusion of the septum primum with the 
septum secundum gives rise to a patent foramen ovale {atrial septal 
defect) but as long as the two septa still overlap, there will be no func- 
tional disability. A patent foramen gives rise to a left-right shunt. 

The right ventricle 

• Receives blood from the right atrium through the tricuspid valve (see 
below). The edges of the valve cusps are attached to chordae tendineae 
which are, in turn, attached below to papillary muscles. The latter are 
projections of muscle bundles on the ventricular wall. 

• The wall of the right ventricle is thicker than that of the atria but not 
as thick as that of the left ventricle. The wall contains a mass of muscu- 
lar bundles known as traheculae carneae. One prominent bundle pro- 
jects forwards from the interventricular septum to the anterior wall. 
This is the moderator hand (or septomarginal trabecula) and is of 
importance in the conduction of impulses as it contains the right branch 
of the atrioventricular bundle. 



• The infundibulum is the smooth walled outflow tract of the right 
ventricle. 

• The pulmonary valve (see below) is situated at the top of the 
infundibulum. It is composed of three semilunar cusps. Blood flows 
through the valve and into the pulmonary arteries via the pulmonary 
trunk to be oxygenated in the lungs. 

The left atrium 

• Receives oxygenated blood from four pulmonary veins which drain 
posteriorly. 

• The cavity is smooth walled except for the atrial appendage. 

• On the septal surface a depression marks the fossa ovalis. 

• The mitral (bicuspid) valve guards the passage of blood from the left 
atrium to the left ventricle. 

The left ventricle (Fig. 7.4) 

• The wall of the left ventricle is considerably thicker than that of the 
right ventricle but the structure is similar. The thick wall is necessary to 
pump oxygenated blood at high pressure through the systemic circula- 
tion. Trabeculae carneae project from the wall with papillary muscles 
attached to the mitral valve cusp edges by way of chordae tendineae. 

• The vestibule is a smooth walled part of the left ventricle which is 
located below the aortic valve and constitutes the outflow tract. 

The heart valves (Fig. 7.5) 

• The purpose of valves within the heart is to maintain unidirectional flow. 

• The mitral (bicuspid) and tricuspid valves are flat. During ventricular 
systole the free edges of the cusps come into contact and eversion is 
prevented by the pull of the chordae. Papillary muscle rupture can 
occur as a complication of myocardial infarction. This is evident clin- 
ically by a pansystolic murmur representing regurgitant flow of blood 
from ventricle to atrium. 

• The aortic and pulmonary valves are composed of three semilunar 
cusps which are cup shaped. During ventricular diastole back-pressure 
of blood above the cusps forces them to fill and hence close. 



The heart I 21 



8 The heart II 



Right coronary 
artery 




Left coronary 
artery 



Anterior 

interventricular 

brancli 




Coronary 
sinus 



Great 

cardiac 

vein 





Marginal 


Posterior 


Middle Small 


Fig.6.1 


artery 


interventricular 


cardiac cardiac 


Tlie coronary arteries. 




branch 


vein vein 


Variations are common 






Fig.6.2 

The venous drainage of the heart 



Atrial conduction 



S-A node 



A-V node 





Fig.ft.4 

An electrocardiogram 



Ventricular conduction 



Fig.S.3 

The direction and timing of the spread 
of action potential in the conducting 
system of the heart. 
Times are in msec 



22 Thorax 



The grooves between the four heart chambers represent the sites that 
offer the least stretch during systole and, for this reason, are where most 
of the vessels supplying the heart are situated. 

The arterial supply of the heart (Fig. g.i) 

The coronary arteries are responsible for supplying the heart itself with 
oxygenated blood. 

The coronary arteries are functional end-arteries and hence follow- 
ing a total occlusion, the myocardium supplied by the blocked artery is 
deprived of its blood supply (myocardial infarction). When the vessel 
lumen gradually narrows due to atheromatous change of the walls, 
patients complain of gradually increasing chest pain on exertion 
(angina) . Under these conditions the increased demand placed on the 
myocardium cannot be met by the diminished arterial supply. Angina 
that is not amenable to pharmacological control can be relieved by 
dilating (angioplasty), or surgically bypassing (coronary artery bypass 
grafting), the arterial stenosis. The latter procediwe is usually per- 
formed using a reversed length of great saphenous vein anastomosed to 
the proximal aorta and then distally to the coronary artery beyond the 
stenosis. Ischaemic heart disease is the leading cause of death in the 
western world and consequently a thorough knowledge of the coronary 
anatomy is essential. 

The origins of the coronary arteries are as follows: 

• The left coronary artery arises from the aortic sinus immediately 
above the left posterior cusp of the aortic valve (see Fig. 7.5). 

• The right coronary artery arises from the aortic sinus immediately 
above the anterior cusp of the aortic valve (see Fig. 7.5). 

There is considerable variation in size and distribution zones of the 
coronary arteries. For example, in some people the posterior interven- 
tricular branch of the right coronary artery is large and supplies a large 
part of the left ventricle whereas in the majority this is supplied by the 
anterior interventricidar branch of the left coronary. 

Similarly, the sinu-atrial node is usually supplied by a nodal branch 
of the right coronary artery but in 30-40% of the population it receives 
its supply from the left coronary. 

The venous drainage of the heart (Fig. g.2) 

The venous drainage systems in the heart include: 

• The veins which accompany the coronary arteries and drain into the 



right atrium via the coronary sinus. The coronary sinus drains into the 
right atrium to the left of and superior to the opening of the inferior vena 
cava. The great cardiac vein follows the anterior interventricular 
branch of the left coronary and then sweeps backwards to the left in the 
atrioventricular groove. The middle cardiac vein follows the posterior 
interventricular artery and, along with the small cardiac vein which fol- 
lows the marginal artery, drains into the coronary sinus. The coronary 
sinus drains the vast majority of the heart's venous blood. 

• The venae cordis minimi: these are small veins which drain directly 
into the cardiac chambers. 

• The anterior cardiac veins: these are small veins which cross the atri- 
oventricular groove to drain directly into the right atrium. 

The conducting system of the heart (Figs 8.3 and 8.4) 

• The sinu-atrial (SA) node is the pacemaker of the heart. It is situated 
near the top of the crista terminalis, below the superior vena caval 
opening into the right atrium. Impulses generated by the SA node are 
conducted throughout the atrial musculature to effect synchronous 
atrial contraction. Disease or degeneration of any part of the conduc- 
tion pathway can lead to dangerous interruption of heart rhythm. 
Degeneration of the SA node leads to other sites of the conduction path- 
way taking over the pacemaking role, albeit usually at a slower rate. 

• Impulses reach the atrioventricular (AV) node which lies in the 
interatrial septum just above the opening for the coronary sinus. From 
here the impulse is transmitted to the ventricles via the atrioventricular 
bundle (of His) which descends in the interventricular septum. 

• The bundle of His divides into right and left branches which send 
Piu-kinje fibres to lie within the subendocardium of the ventricles. The 
position of the Purkinje fibres accounts for the almost synchronous 
contraction of the ventricles. 

The nerve supply of the heart 

The heart receives both a sympathetic and a parasympathetic nerve 
supply so that heart rate can be controlled to demand. 

• The parasympathetic supply (bradycardic effect): is derived from the 
vagus nerve (p. 25). 

• The sympathetic supply (tachycardic and positively inotropic effect): 
is derived from the cervical and upper thoracic sympathetic ganglia by 
way of superficial and deep cardiac plexuses (p. 25). 



The heart 11 Ti 



9 The nerves of the thorax 



Left common 
carotid artery 

Subclavian vein 

Vagus nerve 

Ligamentum 
arteriosum 
Pulmonary trunk 

Left auricle 

Phrenic nerve 
Left ventricle 



Fig.9.1 

The course and distribution 
of the right phrenic nerve 



Subclavian vein 



Sensory to 

diaphragmatic pleura 

Motor to diaphragm 




Scalenus anterior 



Mediastinal pleura 

EJranches to fibrous 
and parietal pericardium 

Inferior vena cava 




Sensory to 
diaphragmatic peritoneum 



Central tendon 
of diaphragm 



Subclavian artery 

Thoracic duct on side of oesophagus 



Superior intercostal vein 
Arch of aorta 

Left recurrent laryngeal nerve 
Left pulmonary artery 

Posterior pulmonary plexus 
Sympathetic trunk 
Descending aorta 
Greater splanchnic nerve 



Fig.9.2 

The structures on the left 
side of the mediastinum. 
They are all co'^ered with 
the mediastinal pleura 



Oesophageal 

plexus on oesophagus " 



Oesophagus 
Trachea 



Fig.9.3 

The structures on the right 
side of the mediastinum 



Vagus nerve 
Pulmonary artery 




Intercostal vessels 
and nerves 

Posterior 
pulmonary plexus 

Greater 
splanchnic nerve 



Subclavian artery 

Subclavian vein 

Left brachiocephalic 
vein 

Superior vena cava 
Acending aorta 

EJronchus 
Right atrium 
Pulmonary veins 
Hilum of lung 

Phrenic nerve 



Oesophageal 
on oesophagus 



24 Thorax 



The phrenic nerves 

The phrenic nerves arise from the C3, C4 and C5 nerve roots in the 
neclc. 

• The light phrenic nerve (Fig. 9.1) descends along a near vertical 
path, anterior to the lung root, lying on sequentially: the right brachio- 
cephalic vein, the superior vena cava, and the right atrium before pass- 
ing to the inferior vena caval opening in the diaphragm (T8). Here the 
right phrenic enters the caval opening and immediately penetrates the 
diaphragm which it supplies. 

• The left phrenic nerve (Fig. 9.2) descends alongside the left subcla- 
vian artery. On the arch of the aorta it passes over the left superior inter- 
costal vein to descend in front of the left lung root onto the pericardium 
overlying the left ventricle. The left phrenic then pierces the muscular 
diaphragm as a solitary structure. Note: the phrenic nerves do not pass 
beyond the undersurface of the diaphragm. 

• The phrenic nerves are composed mostly of motor fibres which supply 
the diaphragm. However, they also transmit fibres which are sensory 
to the fibrous pericardium, mediastinal pleura and peritoneum as well 
as the central part of the diaphragm. 

Irritation of the diaphragmatic peritoneum is usually referred to the 
C4 dermatome . Hence, upper abdominal pathology such as a peifor- 
ated duodenal idcer often results in pain felt at the shoulder tip. 

The vagi 

The vagi are the 10th cranial nerves (p. 145). 

• The right vagus nerve (Figs 9.3 and 3.2) descends adherent to the thor- 
acic trachea prior to passing behind the lung root to form the posterior 
pulmonary plexus. It finally reaches the lower oesophagus where it 
forms an oesophageal plexus with the left vagus. From this plexus, 
anterior and posterior vagal trunks descend (carrying fibres from both 
left and right vagi) on the oesophagus to pass into the abdomen through 
the oesophageal opening in the diaphragm at the level of TIO. 

• The left vagus nerve (Fig. 9.2) crosses the arch of the aorta and 
its branches. It is itself crossed here by the left superior intercostal 
vein. Below, it descends behind the lung root to reach the oesophagus 
where it contributes to the oesophageal plexus mentioned above (see 
Fig. 3.2). 

Vagal branches 

• The left recurrent laryngeal nerve arises from the left vagus below 
the arch of the aorta. It hoolcs around the ligamentum arteriosum and 
ascends in the groove between the trachea and the oesophagus to reach 
the larynx (p. 139). 

• The right recurrent laryngeal nerve arises from the right vagus in the 
neck and hooks around the right subclavian artery prior to ascending in 
the groove between the trachea and the oesophagus before finally 
reaching the larynx. 



• The recurrent laryngeal nerves supply the mucosa of the upper tra- 
chea and oesophagus as well as providing a motor supply to all of the 
muscles of the larynx (except cricothyroid) and sensory fibres to the 
lower larynx. 

• The vagi also contribute branches to the cardiac and pulmonary 
plexuses. 

The thoracic sympathetic trunic (Figs 9.2 and 9.3, and 

Chapter 53) 

• The thoracic sympathetic chain is a continuation of the cervical 
chain. It descends in the thorax behind the pleura immediately lateral to 
the vertebral bodies and passes under the medial arcuate ligament of the 
diaphragm to continue as the lumbar sympathetic trunk. 

• The thoracic chain bears a ganglion for each spinal nerve; the first 
frequently joins the inferior cervical ganglion to form the stellate gan- 
glion. Each ganglion receives a white ramus communicans containing 
preganglionic fibres from its corresponding spinal nerve and sends 
back a grey ramus, bearing postganglionic fibres. 

Upper limb sympathectomy is used for the treatment of hyperhidro- 
sis and Raynaud syndrome. Surgical .sympathectomy involves excision 
of part of the thoracic sympathetic chain (usually for two interspaces) 
below the level of the stellate ganglion. The latter structure must be 
identified on the neck of the 1st rib. 
Branches: 

• Sympathetic fibres are distributed to the skin with each of the thor- 
acic spinal nerves. 

• Postganglionic fibres from Tl-5 are distributed to the thoracic 
viscera — the heart and great vessels, the lungs and the oesophagus. 

• Mainly preganglionic fibres from T5-1 2 form the splanchnic nerves, 
which pierce the crura of the diaphragm and pass to the coeliac and 
renal ganglia from which they are relayed as postganglionic fibres to 
the abdominal viscera (cf. fibres to the suprarenal medulla which are 
preganglionic). These splanchnic nerves are the: greater splanchnic 
(T5-10), lesser splanchnic (TIO— 11) and lowest splanchnic (T12). 
They lie medial to the sympathetic trunk on the bodies of the thoracic 
vertebrae and are quite easily visible through the parietal pleura. 

The cardiac plexus 

This plexus is for descriptive purposes divided into superficial and deep 
parts. It consists of sympathetic and parasympathetic efferents as well 
as afferents. 

• Cardiac branches from the plexus supply the heart where they: 
accompany coronary arteries for vasomotor control and supply the 
sinu-atrial and atrioventricular nodes for cardio-inhibitory and cardio- 
acceleratory purposes. 

• Pulmonary branches supply the bronchial wall smooth muscle (con- 
trolling diameter) and pulmonary blood vessels for vasomotor control. 



The nerves of the thorax 25 



10 Surface anatomy of the thorax 



Transverse fissure h- 
Oblic^ue fissure — 



Fig.10.1 

The surface markings of tlie 
lungs and pleural cavities 




Cervical plexus 



Cardiac notch of lung 



Costodiaphragmatic recess 



Apexof lower lung 

Obliq^ue fissure 

EJeginning of transverse fissure 

Costodiaphragmatic recess 



Fig.10.2 

The surface markings of the heart. 
The areas of auscultation for the 
aortic, pulmonary, mitral and 
tricuspid valves are indicated by letters 




Mid-clavicular line 



26 Thorax 



The anterior thorax 

Landmarks of the anterior thorax include: 

• The angle of Louis {sternal angle): formed by the joint between the 
manubrium and body of the sternum. It is an important landmark as the 
2nd costal cartilages articulate on either side and by following this line 
onto the 2nd rib, further ribs and intercostal spaces can be identified. 
The sternal angle corresponds to a horizontal point level with the inter- 
vertebral disc between T4 and T5. 

• The suprasternal notch: situated in the midline between the medial 
ends of the clavicles and above the upper edge of the manubrium. 

• The costal margin: formed by the lower borders of the cartilages of 
the 7th, 8th, 9th and lOthribsandtheendsof the 11th and 12th ribs. 

• The xiphisternal joint: formed by the joint between the body of the 
sternum and xiphisternum. 

The posterior thorax 

Landmarks of the posterior thorax include: 

• The first palpable spinous process is that of C7 (vertebra prominens). 
Cl-6 vertebrae are covered by the thick ligamentum nuchae. The 
spinous processes of the thoracic vertebrae can be palpated and counted 
in the midline posteriorly. 

• The scapula is located on the upper posterior chest wall. In slim sub- 
jects the superior angle, inferior angle, spine and medial (vertebral) 
border of the scapula are easily palpable. 

Lines of orientation 

These are imaginary vertical lines used to describe locations on the 
chest wall. These include: 

• The mid-clavicular line: a vertical line from the midpoint of the clav- 
icle downwards. 

• The anterior andposterior axillary lines: from the anterior and poster- 
ior axillary folds, respectively, vertically downwards. 

• The mid-axillary line: from the midpoint between anterior and poster- 
ior axillary lines vertically downwards. 

Vertebral levels 

Palpable bony prominences can be used to identify the location of 
important underlying structures. The following bony landmarks and 
their corresponding vertebral levels are given: 

• Suprasternal notch: T2/3. 

• Sternal angle (angle of Louis): T4/5. 

• Superior angle of the scapida: T2. 

• Inferior angle of the scapula: T8. 

• Xiphisternal joint:T9. 

• Subcostal plane (lowest part of the costal margin): L3. 

The surface markings of thoracic structures 

The trachea 

The trachea commences at the lower border of the cricoid cartilage (C6 
vertebral level). It runs downwards in the midline and ends slightly to 
the right by bifurcating into the left and right main bronchi. The bifurca- 
tion occurs at the level of the sternal angle (T4/5). 

The pleura (Fig. 10.1) 

The apex of the pleura projects about 2.5 cm above the medial third of 
the clavicle. The lines of pleural reflection pass behind the sternoclavicu- 
lar joints to meet in the midline at the level of the sternal angle. The 
right pleura then passes downwards to the 6th costal cartilage. The left 



pleura passes laterally for a small distance at the 4th costal cartilage and 
descends vertically lateral to the sternal border to the 6th costal cartil- 
age. From these points both pleurae pass posteriorly and in so doing 
cross the 8th rib in the mid-clavicular line, the 10th rib in the mid- 
axillary line and finally reach the level of the 1 2th rib posteriorly. 

The lungs (Fig. 10.1) 

The apex and mediastinal border of the right lung follow the pleural 
outline. In mid-inspiration the right lung lower border crosses the 6th 
rib in the mid-clavicular line, the 8th rib in the mid-axillary line and 
reaches the level of the 10th rib posteriorly. The left lung borders are 
similar to those of the right except that the mediastinal border arches 
laterally (the cardiac notch) but then resumes the course mentioned 
above. 

• The oblique fissure: is represented by an oblique line drawn from a 
point 2.5 cm lateral to the 5th thoracic spinous process to the 6th costal 
cartilage anteriorly. The oblique fissures separate the lungs into upper 
and lower lobes. 

• The transverse fissure: is represented by a line drawn horizontally 
from the 4th costal cartilage to a point where it intersects the oblique 
fissure. The fissure separates the upper and middle lobes of the right 
lung. 

The heart 

• The borders of the heart are illustrated by joining the four points 
shown (Fig. 10.2). 

• The apex of the left ventricle corresponds to where the apex beat is 
palpable. The surface marking for the apex beat is in the 5th intercostal 
space in the mid-clavicular line. 

• See Fig. 10.2 for optimal sites of valvular auscultation. 

The great vessels 

• The aortic arch: arches antero-posteriorly behind the manubrium. 
The highest point of the arch reaches the midpoint of the manubrium. 

• The brachiocephalic artery and left common carotid arteiy: ascend 
posterior to the manubrium. 

• The brachiocephalic veins: are formed by the confluence of the inter- 
nal jugular and subclavian veins. This occurs posterior to the sterno- 
clavicular joints. 

• The superior vena cava: is formed by the confluence of the left and 
right brachiocephalic veins between the 2nd and 3rd right costal cartil- 
ages at the right border of the sternum. 

The breast 

The base of the breast (p. 69) is constant, overlying the 2nd to the 6th 
ribs and costal cartilages anteriorly and from the lateral border of the 
sternum to the mid-axillary line. The position of the nipple is variable 
in the female but in the man it is usually in the 4th intercostal space in 
the mid-clavicular line. 

The internal thoracic vessels 

These arteries and veins descend 1 cm lateral to the edge of the 
sternum. 

The diaphragm 

In mid-inspiration the highest part of the right dome reaches as far as 
the upper border of the 5th rib in the mid-clavicular line. The left dome 
reaches only the lower border of the 5th rib. 



Surface anatomy of the thorax 27 



11 The abdominal wall 



Fig.11.1 

Two muscles of the anterior 
abdominal wall. 

The external obliq^ue (on the right) and 
the internal oblio|_ue (on the left) 



Serratus 
anterior 



Linea 
semilunaris 



Superficial 
inguinal ring 




Cut edge of external oblique 

Linea alba 

Cut edge of external obliq_ue 

Internal obliq^ue 

Anterior superior iliac spine 

Inguinal ligament 
Conjoint tendon 
Pubic tubercle 





Rectus abdominis 

Deep layer of 
superficial fascia 



Colles' fascia 
Fascia penis 



Dartos 
muscle 



Fig.11.2 

The fibrous layer of superficial fascia 
can be likened tea pairof bathing trunks 
sewn to the thigh below the inguinal 
ligament and clinging to the penis and 
scrotum (except for the glans) 



Fig.11.3 

Transverse sections through 

the rectus sheath. 

A: above the costal margin 

B: above the umbilicus 

C: above the pubic symphysis 



Superior 
epigastric 
artery — 



Inferior 

epigastric 

artery 




Linea alba 
Rectus abdominis 
External obliq^ue 

Costal cartilages 



External oblique 
Internal oblique 
Transversus abdominis 
Transversalis fascia 

External oblique 
Internal oblique 
Transversus abdominis 
Peritoneum 



28 Abdomen and pelvis 



(a) 



Femoral artery 
and vein in 
femoral slieatli 



Internal obliq_ue 



Femoral artery 
and vein in 
femoral sheath 




External oblic^ue 
aponeurosis 

Superficial ring 

Ilioinguinal nerve 

Spermatic cord 
Femoral canal 

Transversus 

Position of deep ring 

Transversalis fascia 

Position of 
superficial ring 

Femoral canal 



Fig.11.4 

The inguinal canal. 

(a) The superficial inguinal ring. The external 
spermatic fascia has been removed 

(b) After removal of the external oblio|_ue 




Testicular artery and 
pampiniform plexus of 
veins 

Vas deferens 

Lymphatics 

Internal spermatic 

fascia 

Cremasteric fascia and 

muscle (striated) 

External spermatic 

fascia 



Fig.11.5 

A schematic cross section through the spermatic cord 



Anterior cutaneous 
branches of 
Intercostal nerves 
T7 



Iliohypogastric 
(lateral branch) 

Iliohypogastric 
(anterior cutaneous) 
Ilioinguinal 




Internal thoracic 

Musculophrenic 
Superior epigastric 

Lumbar 

Para-umbilical veins 
anastomose with 
epigastric veins 



Fig.11.6 

The nerves and vessels of the abdominal wall 



The abdominal wall 29 



The anterior abdominal wall comprises: skin, superficial fascia, abdom- 
inal muscles (and their respective aponeuroses), transversalis fascia, 
extraperitoneal fat, and parietal peritoneum. 

Skin (Fig. 11.6) 

The skin of the abdominal wall is innervated by the anterior rami of the 

lower six thoracic intercostal and iliohypogastric (LI) nerves. 

Fascia (Fig. 11.2) 

There is no deep fascia in the trunk. The superficial fascia is composed 
of two layers: 

• A superficial fatty layer — Camper's fascia — which is continuous with 
the superficial fat over the rest of the body. 

• A deep fibrous (membranous) layer — Scarpa' s fascia — which fades 
above and laterally but below blends with the fascia lata of the thigh 
just below the inguinal ligament and extends into: the penis as a tubular 
sheath; the wall of the scrotum and posteriorly; the perineum where it 
fuses with the perineal body and posterior margin of the perineal mem- 
brane. It fuses laterally with the pubic arch. The fibrous fascial layer is 
referred to as Colles' fascia in the perineum. 

Muscles of tlie anterior abdominal wall (Fig. u.i) 

These comprise: external oblique, internal oblique, transversus abdo- 
minis, rectus abdominis and pyramid alls (see Muscle index, p. 162). 

As in the intercostal space, the neurovascular structures pass in the 
neurovascular plane between internal oblique and transversus muscle 
layers. 

The rectus sheath (Fig. 11.3) 

The rectus sheath encloses the rectus muscles. It contains also the super- 
ior and inferior epigastric vessels and anterior rami of the lower six 
thoracic nerves. 

The sheath is made up from the aponeuroses of the muscles of the 
anterior abdominal wall. The linea alba represents the fusion of the 
aponeuroses in the midline. Throughout the major part of the length of 
the rectus the aponeuroses of external oblique and the anterior layer 
of internal oblique lie in front of the muscle and the posterior layer of 
internal oblique and transversus behind. The composition of the sheath 
is, however, different above the costal margin and above the pubic 
symphysis: 

• Above the costal margin: only the external oblique aponeurosis is 
present and forms the anterior sheath. 

• Above the pubic symphysis: about halfway between the umbilicus 
and pubic symphysis the layers passing behind the rectus muscle gradu- 
ally fade out and from this point all aponeuroses pass anterior to the 
rectus muscle, leaving only the transversalis fascia. 

The lateral border of the rectus — the linea semilunaris — can usually 
be identified in thin subjects. It crosses the costal margin in the trans- 
pyloric plane. 

Three tendinous intersections firmly attach the anterior sheath wall 
to the muscle itself. They are situated at the level of the xiphoid, the 
umbilicus and one between these two. These give the abdominal 'six- 
pack' appearance in muscular individuals. 

Arteries of the abdominal wall (Fig. 11.6) 

These include the superior and inferior epigastric arteries (branches of 
the internal thoracic and external iliac arteries, respectively) and the 



deep circumflex iliac artery (a branch of the external iliac artery) an- 
teriorly. The two lower intercostal and four lumbar arteries supply the 
wall posterolaterally. 

Veins of the abdominal wall (Fig. 11.6) 

The abdominal wall is a site of porto-systemic anastomosis. The lateral 
thoracic, lumbar and superficial epigastric tributaries of the systemic 
circulation anastomose around the umbilicus with the para-umbilical 
veins which accompany the ligamentum teres and drain into the portal 
circulation. 

Lymph drainage of the abdominal wall 

Seep. 35. 

The inguinal canal (Fig. 11.4) 

The canal is approximately 4 cm long and allows the passage of the 
spermatic cord (round ligament in the female) through the lower ab- 
dominal wall. The canal passes obliquely from the deep inguinal ring 
in a medial direction to the superficial inguinal ring. 

• The deep ring: is an opening in the transversalis fascia. It lies half- 
way between the anterior superior iliac spine and the pubic tubercle. 
The inferior epigastric vessels pass medial to the deep ring. 

• The superficial ring: is not a ring but a triangular-shaped defect in 
the external oblique aponeurosis lying above and medial to the pubic 
tubercle. 

The walls of the inguinal canal (Fig. 1 1 .4) 

• Anterior: external oblique covers the length of the canal anteriorly. 
It is reinforced in its lateral third by internal oblique. 

• Superior: internal oblique arches posteriorly to form the roof of the 
canal. 

• Posterior: transversalis fascia forms the lateral part of the posterior 
wall. The conjoint tendon (the combined common insertion of the inter- 
nal oblique and transversus into the pectineal line) forms the medial 
part of the posterior wall. 

• Inferior: the inguinal ligament. 

Contents of the inguinal canal 

• The spermatic cord (or round ligament in the female). 

• The ilioinguinal nerve (LI). 

The spermatic cord (Fig. 11.5) 

The spermatic cord is covered by three layers which arise from the 
layers of the lower abdominal wall as the cord passes through the 
inguinal canal. These are the: 

• External spermatic fascia: from the external oblique aponeurosis. 

• Cremasteric fascia and muscle: from the internal oblique 
aponeurosis. 

• Internal spermatic fascia: from the transversalis fascia. 
The contents of the spermatic cord include the: 

• Ductus (vas) deferens (or round ligament). 

• Testicular artery: a branch of the abdominal aorta. 

• Pampiniform plexus of veins: these coalesce to form the testicular 
vein in the region of the deep ring. 

• Lymphatics: from the testis and epididymis draining to the pre- 
aortic nodes. 

• Autonomic nerves. 



30 Abdomen and pelvis 



12 The arteries of the abdomen 



Coellac 

Superior 
mesenteric, 



Inferior 
mesenteric 




Inferior phrenic 



Suprarenal 
Renal 
Ureteric branch 



Lumbar 



Gonadal 



Median sacral 



Cystic 



Fig.12.1 

The abdominal aorta and its brandies. 
Red labels: ventral branches 
Blue labels: lateral branches 
Green labels: branches to body wall 



Common hepatic 

Gastroduodenal 

Superior — 
pancreatico' 
duodenal 
Right 



gastro- 
epiploic 

Inferior 

pancreatico' 

duodenal 



Superior 
pancreaticoduodenal 

Inferior 
pancreaticoduodenal 




Superior 
mesenteric 



Right and left hepatic 
Right gastric 



Left gastric 




Oesophageal 
branches 

Short gastric 

Spleen 
Splenic 

Pancreatic 
branches 

Left 
gastroepiploic 

Omental branch 



Jejunal and 
Superior ''®^' branches 

mesenteric 
artery 

Fig.12.2 

The coeliac artery and its branches. 

The three primary branches are labelled in red 



Middle colic 

Jejunal and 
ileal branches 



Right colic 
Ileocolic 

] Anterior and posterior 
caecal branches 



Fig.12.3 

The superior mesenteric artery and its branches 



Appendicular 



The arteries of the abdomen 31 



Right colic artery 
Ileocolic artery 



Anterior and posterior 
caecal branches 



Fig.12.4 

The blood supply of theappendix 




Mesentery 
Ileal branch 



lleocaecal fold (bloodless fold of Treves) 

Meso-appendix 

Appendicular artery 



Middle colic 

(from s.mesenteric) 




Marginal artery 
Inferior mesenteric 
Left colic 

Sigmoid branches 



Superior rectal 



Anal canal 



Inferior rectal (a branch of the internal pudendal) 



Fig.12.5 

The inferior mesenteric artery and its branches. 

Note the anastomosis with the inferior rectal artery (green) halfway down the anal canal 



The abdominal aorta (Fig. 12. i) 

The abdominal aorta is a continuation of tlie tlioracic aorta as it passes 
under tlie median arcuate ligament of tfie diapfiragm. It descends in tlie 
retroperitoneum and ultimately bifurcates into left and right common 
iliac arteries to the left of the midline at the level of L4. The vertebral 
bodies and intervertebral discs lie behind the aorta whilst anteriorly, 
from above downwards, lie its anterior branches, the coeliac plexus, the 
lesser sac, the body of the pancreas, the third part of the duodenum, and 
the parietal peritoneum. The main relation to the right of the abdominal 
aorta is the inferior vena cava whilst to the left lie the duodenojejunal 
junction and inferior mesenteric vein. 



The main abdominal branches of the abdominal aorta include the: 

• Coeliac trunk: supplies the embryonic foregut: from the lower third 
of the oesophagus to the second part of the duodenum. 

• Superior mesenteric artery: supplies the midgut: from the second 
part of the duodenum to the distal transverse colon. 

• Renal arteries. 

• Gonadal arteries. 

• Inferior mesenteric artery: supplies the hindgut: from the distal 
transverse colon to the upper half of the anal canal. 



32 Abdomen and pelvis 



The coeliac trunk (Fig. 12.2) 

This trunk arises from the aorta at the level of T12/L1 and after a short 
course divides into three terminal branches. These include the: 

• Left gastric artery: passes upwards to supply the lower oesophagus 
by branches which ascend through the oesophageal hiatus in the 
diaphragm. The left gastric then descends in the lesser omentum along 
the lesser curve of the stomach which it supplies. 

• Splenic artery: passes along the superior border of the pancreas 
in the posterior wall of the lesser sac to reach the upper pole of the left 
kidney. From here it passes to the hilum of the spleen in the lienorenal 
ligament. The splenic artery also gives rise to short gastric branches, 
which supply the stomach fundus, and a left gastroepiploic branch 
which passes in the gastrosplenic ligament to reach and supply the 
greater curve of the stomach. 

• Hepatic artery: descends to the right towards the first part of the 
duodenum in the posterior wall of the lesser sac. It then passes between 
the layers of the free border of the lesser omentum which conveys it to 
the porta hepatis in close relation to the portal vein and bile duct (these 
structures together constitute the anterior margin of the epiploic fora- 
men). Before reaching the porta hepatis it divides into right and left 
hepatic arteries and from the right branch the cystic artery is usually 
given off. Prior to its ascent towards the porta hepatis the hepatic artery 
gives rise to gastroduodenal and right gastric branches. The latter 
passes along the lesser curve of the stomach to supply it. The former 
passes behind the first part of the duodenum and then branches further 
into superior pancreaticoduodenal and right gastroepiploic branches. 
The right gastroepiploic branch runs along the lower part of the greater 
curvature to supply the stomach. 

The superior mesenteric artery (Fig. 12.3) 

The superior mesenteric artery arises from the abdominal aorta at the 
level of LI. From above downwards, it passes over the left renal vein 
behind the neck of the pancreas, over the uncinate process and anterior 
to the third part of the duodenum. It then passes obliquely downwards 
and towards the right iliac fossa between the layers of the mesentery of 
the small intestine where it divides into its terminal branches. The 
branches of the superior mesenteric artery include the: 



• Inferior pancreaticoduodenal artery: supplies the lower half of the 
duodenum and pancreatic head. 

• Ileocolic artery: passes in the root of the mesentery over the right 
ureter and gonadal vessels to reach the caecum where it divides into ter- 
minal caecal and appendicular branches (Fig. 12.4). 

• Jejunal and ileal branches: a total of 12-15 branches arise from the 
left side of the artery. These branches divide and reunite within the 
small bowel mesentery to form a series of arcades which then give rise 
to small straight terminal branches which supply the gut wall. 

• Right colic artery: passes horizontally in the posterior abdominal 
wall to supply the ascending colon. 

• Middle colic artery: courses in the transverse mesocolon to supply 
the proximal two-thirds of the transverse colon. 

The renal arteries 

These arise from the abdominal aorta at the level of L2. 

The gonadal arteries (ovarian or testicular) 

These arteries arise from below the renal arteries and descend obliquely 
on the posterior abdominal wall to reach the ovary in the female, or pass 
through the inguinal canal in the male to reach the testis. 

The inferior mesenteric artery (Fig. 12.5) 

The inferior mesenteric artery arises from the abdominal aorta at the 
level of L3. It passes downwards and to the left and crosses the left 
common iliac artery where it changes its name to the superior rectal 
artery. Its branches include: 

• The left colic artery: supplies the distal transverse colon, the splenic 
flexure and upper descending colon. 

• Two or three sigmoid branches: pass into the sigmoid mesocolon 
and supply the lower descending and sigmoid colon. 

• The superior rectal artery: passes into the pelvis behind the rectum 
to form an anastomosis with the middle and inferior rectal arteries. It 
supplies the rectum and upper half of the anal canal. 

The marginal artery (of Drummond) is an anastomosis of the colic 
arteries at the margin of the large intestine. This establishes a strong 
collateral circulation throughout the colon. 



The arteries of the abdomen 33 



1 3 The veins and lymphatics of the abdomen 




Inferior phrenic 

Suprarenal 
Ureteric branch 
Renal 

Lumbar 



Gonadal 
Common iliac 

Median sacral 



Fig.13.1 

The inferior vena cava and its tributaries 



Right gastric 



Cystic 



Portal vein 



Pancreaticoduodenal 



Middle colic 



Right colic 




Oesophageal branches 
Right gastroepiploic 
Spleen 

Splenic 

Inferior mesenteric 

Superior mesenteric 

Left colic 

Sigmoid branches 
Superior rectal 



Fig.13.2 

The portal system. 

Note the anastomoses with the systemic system (orange) in the oesophagus and the anal canal 



34 Abdomen and pelvis 



The portal vein (Fig. 13.2) 

The portal venous system receives blood from the length of gut from 
the lower third of the oesophagus to the upper half of the anal canal as 
well as the spleen, pancreas and gall-bladder. It serves to transfer blood 
to the liver where the products of digestion can be metabolized and 
stored. Blood from the liver ultimately gains access to the inferior vena 
cava by way of the hepatic veins. The portal vein is formed behind the 
neck of the pancreas by the union of the superior mesenteric and splenic 
veins. It passes behind the first part of the duodenum in front of the in- 
ferior vena cava and enters the free border of the lesser omentum. The 
vein then ascends towards the porta hepatis in the anterior margin of the 
epiploic foramen (of Winslo w) in the lesser omentum. At the porta hep- 
atis it divides into right and left branches. The veins that correspond to 
the branches of the coeliac and superior mesenteric arteries drain into 
the portal vein or one of its tributaries. The inferior mesenteric vein 
drains into the splenic vein adjacent to the fourth part of the duodenum. 

Porto-systemic anastomoses 

A number of connections occur between the portal and systemic circula- 
tions. When the direct pathway through the liver becomes congested 
(such as in cirrhosis) the pressure within the portal vein rises and under 
these circumstances the porto-systemic anastomoses form an alternat- 
ive route for the blood to take. The sites of porto-systemic anastomosis 
include: 

• The lower oesophagus (p. 11): formed by tributaries of the left gas- 
tric (portal) and oesophageal veins (systemic via the azygos and hemi- 
azygos veins). 

• The anal canal: formed by the superior rectal (portal) and middle 
and inferior rectal veins (systemic). 

• The bare area of the liver: formed by the small veins of the portal 
system and the phrenic veins (systemic). 

• The periumbilical region: formed by small paraumbilical veins 
which drain into the left portal vein and the superficial veins of the anter- 
ior abdominal wall (systemic). 

Tlie inferior vena cava (Fig. 13. i) 

The inferior vena cava is formed by the union of the common iliac veins 
in front of the body of L5 . It ascends in the retroperitoneum on the right 
side of the abdominal aorta. Along its course, from below upwards, it 
forms the posterior wall of the epiploic foramen of Winslow and is 
embedded in the bare area of the liver in front of the right suprarenal 
gland. The inferior vena cava passes through the caval opening in the 
diaphragm at the level of T8 and drains into the right atrium. 



Tlie lymphatic drainage of the abdomen and pelvis 

The abdominal wall 

Lymph from the skin of the anterolateral abdominal wall above the 
level of the umbilicus drains to the anterior axillary lymph nodes. Effer- 
ent lymph from the skin below the umbilicus drains to the superficial 
inguinal nodes. 

The lymph nodes and trunks 

The two main lymph node groups of the abdomen are closely related to 
the aorta. These comprise the pre-aortic and para-aortic groups. 

• The pre-aortic nodes are arranged around the three ventral branches 
of the aorta and consequently receive lymph from the territories that are 
supplied by these branches. This includes most of the gastrointestinal 
tract, liver, gall-bladder, spleen and pancreas. The efferent vessels from 
the pre-aortic nodes coalesce to form a variable number of intestinal 
trunks which deliver the lymph to the cisterna chyli. 

• The para-aortic nodes axe, arranged around the lateral branches of the 
aorta and drain lymph from their corresponding territories, i.e. the kid- 
neys, adrenals, gonads, and abdominal wall as well as the common iliac 
nodes. The efferent vessels from the para-aortic nodes coalesce to form 
a variable number of lumbar trunks which deliver the lymph to the cis- 
terna chyli. 

Cisterna chyli 

The cisterna chyli is a lymphatic sac that lies anterior to the bodies of 
the 1st and 2nd lumbar vertebrae. It is formed by the confluence of the 
intestinal trunks, the lumbar trunks and lymphatics from the lower tho- 
racic wall. It serves as a receptacle for lymph from the abdomen and 
lower limbs which is then relayed to the thorax by the thoracic duct 
(p. 11). 

The lymphatic drainage of the stomach 

Lymph from the stomach drains to the coeliac nodes. For the purposes 
of description, the stomach can be divided into four quarters where 
lymph drains to the nearest appropriate group of nodes. 

The lymphatic drainage of the testes 

Lymph from the skin of the scrotum and the tunica albuginea drains to 
the superficial inguinal nodes. Lymph from the testes, however, drains 
along the course of the testicular artery to the para-aortic group of 
nodes. Hence, a malignancy of the scrotal skin might result in palpable 
enlargement of the superficial inguinal nodes whereas testicular 
tumours metastasize to the para-aortic nodes. 



The veins and lymphatics of the abdomen 35 



14 The peritoneum 



Subphrenic space 

Diaphragm 

Upper recess of 

omental bursa 

Liver 

Lesser omentum 

Epiploic foramen 

(in the distance) 

Omental bursa 

Pancreas 

Stomach 

Transverse mesocolon 

Duodenum (third part) 

Transverse colon 

Small intestine 

Mesentery 

Greateromentum 
Fusion between layers 
of greater omentum 

Fig.14.1 

A vertical section through the abdomen to show the 

peritoneal relations. 

Lesser sac i i 

Greater sac i i 




Epiploic foramen (of Winslow) 
Portal vein 
Inferior vena cava 
Aorta 



Left kidney 

Splenic artery 

Lienorenal ligament 

Spleen 

Short gastric 

vessels 

Gastrosplenic 

ligament 

Stomach 

Lesser omentum 
Hepatic artery 

Common bile duct 

Liver 

Fig.14.2 

A horizontal section through the abdomen. 

Note howthe epiploic foramen lies between two major veins 




Upper layer of 
coronary ligament 




Left triangular 
ligament 



(a) 



Fundus of 
gall bladder 



Falciform ligament 
Ligamentum teres 

Position of umbilicus 



Upper layer of 
coronary ligament 

Lower layer of 
coronary ligament 

— Gall bladder 




Right 

triangular 

ligament 



covering 
caudate lobe 



Inferior vena cava 



Fig.14.3 

The peritoneal relations of the liver 

(a) Seen from in front 

(b) The same liver rotated in the direction of the arrow to show the upper and posterior surfaces. 

The narrow spaces between the liver and the diaphragm labelled A and E3 are the right and left subphrenic spaces 



Ligamentum teres 

Portal vein, hepatic 
artery and bile duct 
in free edge of lesser 
omentum leading to 
porta hepatis 
Cut edge of lesser 
omentum 
Left triangular 
ligament 
Fissure for 
ligamentum venosum 



36 Abdomen and pelvis 



The mesenteries and layers of the peritoneum 

The transverse colon, stomach, spleen and liver each have attached to 
them two 'mesenteries' — double layers of peritoneum containing arteries 
and their accompanying veins, nerves and lymphatics — while the small 
intestine and sigmoid colon have only one. All the other viscera are re- 
troperitoneal. The mesenteries and their associated arteries are as follows: 

• The colon (Fig. 14.1): (1) The transverse mesocolon (the middle 
colic artery). (2) The posterior two layers of the greater omentum. 

• The stomach (Fig. 14.1): (1) The lesser omentum (the left and right 
gastric arteries and in its free border, the hepatic artery, portal vein and 
bile duct). (2) The anterior two layers of the greater omentum (the right 
and left gastroepiploic arteries and their omental branches). 

• The spleen (Fig. 14.2): (1) The lienorenal ligament (the splenic 
artery). (2) The gastrosplenic ligament (the short gastric and left gas- 
troepiploic arteries). 

• The liver (Fig. 14.3): (1) The, falciform ligament and the two layers 
of the coronary ligament with their sharp edges, the left and right trian- 
gular ligaments. This mesentery is exceptional in that the layers of the 
coronary ligament are widely separated so that the liver has a bare area 
directly in contact with the diaphragm (the obliterated umbilical artery 
in the free edge of the falciform ligament and numerous small veins in 
the bare area, p. 35). (2) The lesser omentutn (already described). 

• The small intestine (Fig. 14.1): (1) The mesentery of the small intes- 
tine (the superior mesenteric artery and its branches). 

• The sigmoid colon: (1) The sigmoid mesocolon (the sigmoid arteries 
and their branches). 

The peritoneal cavity (Figs 14.1 and 14.2) 

• The complications of the peritoneal cavity may best be described by 
starting at the transverse mesocolon. Its two layers are attached to the 
anterior surface of the pancreas, the second part of the duodenum and 
the front of the left kidney. They envelop the transverse colon and con- 
tinue downwards to form the posterior two layers of the greater omen- 
tum, which hangs down over the coils of the small intestine. They then 
turn back on themselves to form the anterior two layers of the omentum 
and these reach the greater curvature of the stomach. The four layers of 
the omentum are fused and impregnated with fat. The greater omentum 
plays an important role in limiting the spread of infection in the peri- 
toneal cavity. 

• From its attachment to the pancreas, the lower layer of the transverse 
mesocolon turns downwards to become the parietal peritoneum of the 
posterior abdominal wall from which it is reflected to form the mesen- 
teiy of the small intestine and the sigmoid mesocolon. 

• The upper layer of the transverse mesocolon passes upwards to form 
the parietal peritoneum of the posterior abdominal wall, covering the 
upper part of the pancreas, the left kidney and its suprarenal, the aorta 
and the origin of the coeliac artery (the 'stomach bed'). It thus forms the 
posterior wall of the omental bursa. It then covers the diaphragm and 
continues onto the anterior abdominal wall. 

• From the diaphragm and anterior abdominal wall it is reflected onto 
the liver to form its 'mesentery' in the form of the two layers of Ihe fal- 
ciform ligament. At the liver, the left layer of the falciform ligament 
folds back on itself to form the sharp edge of the left triangular liga- 



ment while the right layer turns back on itself to form the upper and 
lower layers of the coronary ligament with its sharp-edged right tri- 
angular ligament. The layers of the coronary ligament are widely 
separated so that a large area of liver between them — the hare area — 
is directly in contact with the diaphragm. The inferior vena cava is 
embedded in the bare area (Fig. 14.3). 

• From the undersurface of the liver another 'mesentery' passes from 
the fissure for the ligamentum venosum to the lesser curvature of the 
stomach to form the lesser omentum. 

• The lesser omentum splits to enclose the stomach and is continuous 
with the two layers of the greater omentum already described. The 
lesser omentum has a right free border which contains the portal vein, 
the hepatic artery and the common bile duct. 

• In the region of the spleen there are two more ' mesenteries ' which are 
continuous with the lesser and greater omenta. These are the lienorenal 
ligament, a double layer of peritoneum reflected from the front of the 
left kidney to the hilum of the spleen, and the gastrosplenic ligament 
which passes from the hilum of the spleen to the greater curvature of the 
stomach (Fig. 14.2). 

• The mesentery of the small intestine is attached to the posterior ab- 
dominal wall from the duodenojejunal flexure to the ileocolic junction. 

• The sigmoid mesocolon passes from a V-shaped attachment on the 
posterior abdominal wall to the sigmoid colon. 

• The general peritoneal cavity comprises the main cavity — the greater 
sac — and a diverticulum from it — the omental bursa (lesser sac). The 
omental bursa lies between the stomach and the stomach bed to allow 
free movement of the stomach. It lies behind the stomach, the lesser 
omentum and the caudate lobe of the liver and in front of the structures 
of the stomach bed. The left border is formed by the hilum of the spleen 
and the lienorenal and gastrosplenic ligaments. 

• The communication between the greater and lesser sacs is the epi- 
ploic foramen (foramen ofWinslow). It lies behind the free border of 
the lesser omentum and its contained structures, below the caudate pro- 
cess of the liver, in front of the inferior vena cava and above the first 
part of the duodenum. 

• The subphrenic spaces are part of the greater sac that lies between the 
diaphragm and the upper surface of the liver. There are right and left 
spaces, separated by the falciform ligament. 

• In the pelvis the parietal peritoneum covers the upper two-thirds of 
the rectum whence it is reflected, in the female, onto the posterior 
fornix of the vagina and the back of the uterus to form the recto-uterine 
pouch (pouch of Douglas). In the male it passes onto the back of the 
bladder to form the rectovesical pouch. 

The anterior abdominal wall 

• The peritoneum of the deep surface of the anterior abdominal wall 
shows a central ridge from the apex of the bladder to the umbilicus pro- 
duced by the median umbilical ligament. This is the remains of the 
embryonic urachus. Two medial umbilical ligaments converge to the 
umbilicus from the pelvis. They represent the obliterated umbilical 
arteries of the fetus. The ligamentum teres is a fibrous band in the free 
margin of the falciform ligament. It represents the obliterated left 
umbilical vein. 



The peritoneum 37 



15 The upper gastrointestinal tract I 




Lesser curvature 
Angular incisure- 
Pyloric sphincter 

Duodenum 



Fig.15.1 

The subdivisions of the stomach 



Right crus of dia 
Suprarenal 



Right kidney 



Hepatic 
flexure 



Ascending 
colon 



Cardiac notch 
Fundus 

Body 

Greater curvature 
Pyloric antrum 




Fig.15.2 

The stomach bed. For more detail see fig.19.1. 

The stomach is outlined but the shape is by no means constant 



Aorta 

Spleen 

Splenic artery 
Splenic flexure of colon 

Pancreas 
Descending colon 
Left kidney 



38 Abdomen and pelvis 



The embryonic gut is divided into foregut, midgut and hindgut, sup- 
plied, respectively, by the coeliac, superior mesenteric and inferior 
mesenteric arteries. The foregut extends from the oesophagus to the 
entrance of the common bile duct into the second part of the duodenum. 
The midgut extends down to two-thirds of the way along the transverse 
colon. It largely develops outside the abdomen until this congenital 
'umbilical hernia' is reduced during the 8th-10th week of gestation. 
The hindgut extends down to include the upper half of the anal canal. 

The abdominal oesophagus 

• The abdominal oesophagus measures approximately 1 cm in length. 

• It is accompanied by the anterior and posterior vagal trunks from the 
left and right vagi and the oesophageal branches of the left gastric 
artery. 

• The lower third of the oesophagus is a site of porto-systemic venous 
anastomosis. This is formed between tributaries of the left gastric and 
azygos veins (p. 11). 

The stomach (Figs 15.1 and 15.2) 

• The notch on the lesser curve, at the junction of the body and pyloric 
antrum, is the incisura angiilaris. 

• The pyloric sphincter controls the release of stomach contents into 
the duodenum. The sphincter is composed of a thickened layer of circu- 
lar smooth muscle which acts as an anatomical, as well as physiolo- 
gical, sphincter. The junction of the pylorus and duodenum can be seen 
externally as a constriction with an overlying vein — the prepyloric vein 
(of Mayo). 

• The cardiac orifice represents the point of entry for oesophageal con- 
tents into the stomach. The cardiac sphincter acts to prevent reflux of 
stomach contents into the oesophagus. Unlike the pylorus there is no 
discrete anatomical sphincter at the cardia; however, multiple factors 
contribute towards its mechanism. These include: the arrangement of 
muscle fibres at the cardiac orifice acting as a physiological sphincter; 
the angle at which the oesophagus enters the stomach producing a valve 
effect; the right crus of the diaphragm surrounding the oesophagus and 
compression of the short segment of intra-abdominal oesophagus by in- 
creases in intra-abdominal pressure during straining, preventing reflux. 

• The lesser omentum is attached to the lesser curvature and the greater 
omentum to the greater curvature. The omenta contain the blood and 
lymphatic supply to the stomach. 

• The mucosa of the stomach is thrown into folds — rugae. 

• Blood supply (see Fig. 12.2): the arterial supply to the stomach is 
exclusively from branches of the coeliac axis. Venous drainage is to the 
portal system (see Fig. 13.2). 

• Nerve supply: the anterior and posterior vagal trunks arise from the 
oesophageal plexuses and enter the abdomen through the oesophageal 
hiatus. The hepatic branches of the anterior vagus pass to the liver. The 
coeliac branch of the posterior vagus passes to the coeliac ganglion 
from where it proceeds to supply the intestine down to the distal trans- 



verse colon. The anterior and posterior vagal trunks descend along the 
lesser curve as the anterior and posterior nerves of Latarjet from which 
terminal branches arise to supply the stomach. The vagi provide a 
motor and secretory supply to the stomach. The latter includes a supply 
to the acid-secreting part — the body. 

The duodenum (Figs 19.1 and 19.2) 

The duodenum is the first part of the small intestine. It is approximately 
25 cm long and curves around the head of the pancreas. Its primary 
function is in the absorption of digested products. Despite its relatively 
short length the surface area is greatly enhanced by the mucosa being 
thrown into folds bearing villi which are visible only at a microscopic 
level. With the exception of the first 2.5 cm, which is completely cov- 
ered by peritoneum, the duodenum is a retroperitoneal structure. It is 
considered in four parts: 

• First part (5 cm). 

• Second part (7.5 cm) — this part descends around the head of the 
pancreas. Internally, in the mid-section, a small eminence may be 
found on the posteromedial aspect of the mucosa — the duodenal 
papilla. This structure represents the site of the common opening 
of the bile duct and main pancreatic duct (ofWirsung). The sphinc- 
ter of Oddi guards this common opening. A smaller subsidiary 
pancreatic duct (of Santorini) opens into the duodenum a small 
distance above the papilla. 

• Third part (10 cm) — this part is crossed anteriorly by the root of 
the mesentery and superior mesenteric vessels. 

• Fourth part (2.5 cm) — this part terminates as the duodenojejunal 
junction. The termination of the duodenum is demarcated by a 
peritoneal fold stretching from the junction to the right crus of 
the diaphragm covering the suspensory ligament of Treitz. The 
terminal part of the inferior mesenteric vein lies adjacent to the 
duodenojejunal junction and serves as a useful landmark. 

• Blood supply (see Fig. 12.2): the superior and inferior pancreatico- 
duodenal arteries supply the duodenum and run between this structure 
and the pancreatic head. The superior artery arises from the coeliac axis 
and the inferior from the superior mesenteric artery. 

Peptic ulcer disease 

Most peptic ulcers occur in the stomach and proximal duodenum. They 
arise as a result of an imbalance between acid secretion and mucosal 
defences. Helicobacter pylori infection is a significant aetiological 
factor and the eradication of this organism, as well as the attenuation 
of acid secretion, form the cornerstones of medical treatment. In a 
minority of cases the symptoms are not controlled by medical treatment 
alone and surgery is required. 'Very highly selective vagotomy' is a 
technique where only the afferent vagal fibres to the acid-secreting 
body are denervated thus not compromising the motor supply to the 
stomach and hence bypassing the need for a drainage procedure (e.g. 
gastrojejunostomy) . 



The upper gastrointestinal tract I 39 



16 The upper gastrointestinal tract II 



Kedder 
wall 



Jejunum 



Fig.16.1 




From superior mesenteric artery 



Jejunal branches 



Simple arcades 



Ileum 



Thicker wall 
(feels full) 




Ileal branches 



Multiple arcades 



Thinnerwall 
(fee Is empty) 



Thejejunum and the ileum can be distinguished by their colour, feel and the complexity of the arterial arcades 




Fig.16.2 

Small bowel obstruction, showing dilated bowel loops 



40 Abdomen and pelvis 



The small intestine (Fig. le.i) 

The small intestine is approximately 6 m long and comprises the duo- 
denum, jejunum and ileum. A large internal surface area throughout the 
small intestine facilitates absorption of digested products. The small 
intestine is suspended from the posterior abdominal wall by its mesen- 
tery which contains the superior mesenteric vessels, lymphatics and auto- 
nomic nerves. The origin of the mesentery measures approximately 15 
cm and passes from the duodenojejunal flexure to the right sacro-iliac 
joint. The distal border is obviously the same length as the intestine. 
No sharp distinction occurs between the jejunum and ileum; however, 
certain characteristics help distinguish between them: 

• Excluding the duodenum, the proximal two-fifths of the small intes- 
tine comprises jejunum whereas the remaining distal three-fifths com- 
prises ileum. Loops of jejunum tend to occupy the umbilical region 
whereas the ileum occupies the lower abdomen and pelvis. 

• The mucosa of the small intestine is thrown into circular folds — the 
valvidae conniventes. These are more prominent in the jejunum than in 
the ileum. 

• The diameter of the jejunum tends to be greater than that of the ileum. 

• The mesentery to the jejunum tends to be thicker than that for the 
ileum. 



• The superior mesenteric vessels (see Fig. 12.3) pass over the third 
part of the duodenum to enter the root of the mesentery and pass 
towards the right iliac region on the posterior abdominal wall. Jejunal 
and ileal branches arise which divide and re-anastomose within the 
mesentery to produce arcades. End-artery vessels arise from the 
arcades to supply the gut wall. The arterial supply to the jejunum con- 
sists of few arcades and little terminal branching whereas the vessels to 
the ileum form numerous arcades and much terminal branching of end- 
arteries passing to the gut wall. 

Small bowel obstruction (Fig. 16.2) 

Small bowel obstruction (SBO) can occur due to luminal, mural or 
extraluminal factors that result in luminal blockage. Post surgical 
adhesions and herniae are the most frequent causes. Many cases 
resolve with conservative measures only; however, ifatry deterioration 
in the clinical picture occurs to suggest intestinal infarction or perfora- 
tion an exploratory laparotomy is mandatory. The classical X-ray fea- 
tures of SBO are those of dilated small bowel loops. These can be 
distinguished from large bowel as the valvulae conniventes (present 
only in the small bowel) can be identified traversing the entire lumen 
whereas the small bowel haustra only partially traverse the lumen. 



The upper gastrointestinal tract // 41 



17 The lower gastrointestinal tract 



Teniae coli 



Appendices 
epiploicae 

I5.et rocolic 
Retrocaecal 




Retro-ileal 
Pre-ileal 

Subcaecal 
Ovary in female 



Fig.17.1 

Tlie various positions in wliicli tlie appendix may be found. 

In the pelvic position the appendix may be close to the ovary in the female 



Longitudinal muscle 
Circular muscle 
Levator an i 

Obturator internus 

Fat of ischiorectal fossa 



Sphincter 
ani 
extern us 



Pudendal canal 
Adductor muscles 



Rectum 




Submucosa 
Sphincterani internus 



Inferior rectal 
veselsand nerve 



Fig.17.2 

A coronal section through the pelvis to show the 
anal sphincters and the ischiorectal fossa 



42 Abdomen and pelvis 



The caecum and colon (Figs 17.1, 12.3, 12.5) 

In adults, the large bowel measures approximately 1.5 m. The caecum, 
ascending, transverse, descending and sigmoid colon have similar 
characteristic features. These are that they possess: 

• Appendices epiploicae (Fig. 17.1): these are fat-laden peritoneal tags 
present over the surface of the caecum and colon. 

• Teniae coli (Fig. 17.1): these are three flattened bands representing 
the condensed longitudinal muscular coat of the large intestine. They 
course from the base of the appendix (and form a useful way of locating 
this structure at operation) to the recto-sigmoid junction. 

• Sacculations: because the teniae are shorter than the bowel itself the 
colon takes on a sacculated appearance. These sacculations are visible 
not only at operation but also radiographically . On a plain abdominal X- 
ray, the colon, which appears radiotranslucent because of the gas within, 
has shelf-like processes (haustra) which partially project into the lumen. 

The transverse and sigmoid colon are each attached to the posterior 
abdominal wall by their respective mesocolons and are covered en- 
tirely by peritoneum. Conversely, the ascending and descending colon 
normally possess no mesocolon. They are adherent to the posterior 
abdominal wall and covered only anteriorly by peritoneum. 

The appendix (Fig. 17.1) 

The appendix varies enormously in length but in adults it is approxim- 
ately 5-15 cm long. The base of the appendix arises from the postero- 
medial aspect of the caecum; however, the lie of the appendix itself is 
highly variable. In most cases the appendix lies in the retrocaecal posi- 
tion but other positions frequently occur. The appendix has the follow- 
ing characteristic features: 

• It has a small mesentery which descends behind the terminal ileum. 
The only blood supply to the appendix, the appendicular artery (a 
branch of the ileocolic), courses within its mesentery (see Fig. 12.4). In 
cases of appendicitis the appendicular artery ultimately thromboses. 
When this occurs, gangrene and perforation of the appendix inevitably 
supervene. 

• The appendix has a lumen which is relatively wide in infants and gra- 
dually narrows throughout life, often becoming obliterated in the elderly. 

• The teniae coli of the caecum lead to the base of the appendix. 

• The bloodless fold of Treves (ileocaecal fold) is the name given to a 
small peritoneal reflection passing from the anterior terminal ileum to 
the appendix. Despite its name it is not an avascular structure! 

Appendicectomy is performed most commonly through a grid-iron 
muscle-splitting incision. The appendi.x is first located and then deliv- 
ered into the wound. The mesentery of the appendix is then divided and 
ligated. The appendix is then tied at its base, excised and removed. 
Most siu-geons still opt to invaginate the appendix stump as a precau- 
tionary measure against slippage of the stump ligature. 



The rectum (Figs 17.2, 12.5) 

• The rectum measures 10-15 cm in length. It commences in front of 
the 3rd sacral vertebra as a continuation of the sigmoid colon and fol- 
lows the curve of the sacrum anteriorly. It turns backwards abruptly in 
front of the coccyx to become the anal canal. 

• The mucosa of the rectum is thrown into three horizontal folds that 
project into the lumen — the valves of Houston. 

• The rectum lacks haustrations. The teniae coli fan out over the rec- 
tum to form anterior and posterior bands. 

• The rectum is slightly dilated at its lower end — the ampulla, and is 
supported laterally by the levator ani. 

• Peritoneum covers the upper two-thirds of the rectum anteriorly but 
only the upper third laterally. In the female it is reflected forwards onto 
the uterus forming the recto-uterine pouch {pouch of Douglas). The 
rectum is separated from anterior structures by a tough fascial sheet 
— the rectovesical (Denonvilliers) fascia. 

The anal canal (Fig. 17.2) 

The anorectal junction is slung by the puborectalis component of lev- 
ator ani which pulls it forwards. The canal is approximately 4 cm long 
and angled postero-inferiorly. Developmentally the midpoint of the 
anal canal is represented by the dentate line. This is the site where the 
proctodeum (ectoderm) meets endoderm. This developmental implica- 
tion is reflected by the following characteristics of the anal canal: 

• The epithelium of the upper half of the anal canal is columnar. In con- 
trast the epithelium of the lower half of the anal canal is squamous. The 
mucosa of the upper canal is thrown into vertical columns (of Mor- 
gagni). At the bases of the columns are valve-like folds (valves of Ball). 
The level of the valves is termed the dentate line. 

• The blood supply to the upper anal canal (see Fig. 12.5) is from the 
superior rectal artery (derived from the inferior mesenteric artery) 
whereas the lower anal canal is supplied by the inferior rectal artery 
(derived from the internal iliac artery). As mentioned previously, the 
venous drainage follows suit and represents a site of porto-systemic 
anastomosis (see p. 35). 

• The upper anal canal is insensitive to pain as it is supplied by auto- 
nomic nerves only. The lower anal canal is sensitive to pain as it is sup- 
plied by somatic innervation (inferior rectal nerve). 

• The lymphatics from the upper canal drain upwards along the super- 
ior rectal vessels to the internal iliac nodes whereas lymph from the 
lower anal canal drains to the inguinal nodes. 

The anal sphincter 

See Chapter 25. 



The lower gastrointestinal tract 43 



18 The liver, gall-bladder and biliary tree 



Hepatic vein 




^:a^ 3 




Opening in central tendon 
of diapliragm 



Liver 



Spleen 



Portal vein 



Splenic vein 

Inferior mesenteric vein 



Superior mesenteric vein 



Fig.15.1 

The venous circulation through the liver. 

The transmission of blood from the portal system to the inferior vena cava 

is via the liver lobules (fig. 18.2) 



Periportal 

connective 

tissue 

Direction of 
bile flow 



Central vein 



Bile duct 



(a) 




Bile duct 

EJranch of hepatic artery 

EJranch of portal vein 

Direction of blood flow 




E3ilecanaliculi 

Vein 

Artery 



] Sinusoids 



Central vein 



Fig.16.2 

(a) A liver lobule to show the direction of blood flow from the portal system to the centrilobular veins 
and thence to the inferior vena cava 

(b) The blood flowthrough the sinusoids of the liver lobule and the passage of bile from the bile 
canaliculi to the bile ducts 



44 Abdomen and pelvis 



The liver (see Fig. 14.3) 

• The liver predominantly occupies the right hypochondrium but the 
left lobe extends to the epigastrium. Its domed upper (diaphragmatic) 
surface is related to the diaphragm and its lower border follows the con- 
tour of the right costal margin. When the liver is enlarged the lower 
border becomes palpable below the costal margin . 

• The liver anatomically consists of a large right lobe, and a smaller left 
lobe. These are separated antero-superiorly by the falciform ligament 
and postero-inferiorly hy fissures for the ligamentum venosum and liga- 
mentiim teres. In the anatomical classification the right lobe includes 
the caudate and quadrate lobes. Functionally, however, the caudate and 
most of the quadrate lobes are units of the left lobe as they receive their 
blood supplies from the left hepatic artery and deliver their bile into the 
left hepatic duct. Hence, the functional classification of the liver defines 
the right and left lobes as separated by a vertical plane extending pos- 
teriorly from the gall-bladder to the inferior vena cava (IVC). 

• When the postero-inferior {visceral) surface of the liver is seen from 
behind an H-shaped arrangement of grooves and fossae is identified. 
The boundaries of the H are formed as follows: 

• Right anterior limb — the gall-bladder fossa. 

• Right posterior limb — the groove for the IVC. 

• Left anterior limb — the fissure containing the ligamentum teres 
(the fetal remnant of the left umbilical vein which returns oxygen- 
ated blood from the placenta to the fetus). 

• Left posterior limb — the fissure for the ligamentum venosum (the 
latter structure is the fetal remnant of the ductus venosus; in the 
fetus the ductus venosus serves to partially bypass the liver by 
transporting blood from the left umbilical vein to the IVC). 

• Horizontal limb — the porta hepatis. The caudate and quadrate 
lobes of the liver are the areas defined above and below the hori- 
zontal bar of the H, respectively. 

• The porta hepatis is the hilum of the liver. It transmits (from pos- 
terior to anterior) the: portal vein (Fig. 18.1); branches of the hepatic 
artery and hepatic ducts. The porta is enclosed within a double layer of 
peritoneum — the lesser omentum, which is firmly attached to the liga- 
mentum venosum in its fissure. 

• The liver is covered by peritoneum with the exception of the 'bare 
area'. 

• The liver is made up of multiple functional units — lobules (Fig. 18.2). 
Branches of the portal vein and hepatic artery transport blood through 
portal canals into a central vein by way of sinusoids which traverse the 
lobules. The central veins ultimately coalesce into the right, left and 
central hepatic veins which drain blood from corresponding liver areas 
backwards into the IVC. The portal canals also contain tributaries of the 



hepatic ducts which serve to drain bile from the lobule down the biliary 
tree from where it can be concentrated in the gall-bladder and eventu- 
ally released into the duodenum. The extensive length of gut that is 
drained by the portal vein explains the predisposition for intestinal 
tumours to metastasize to the liver. 

The gall-bladder (see Fig. i4.3) 

The gall-bladder lies adherent to the undersurface of the liver in the 
transpyloric plane (p. 53) at the junction of the right and quadrate lobes. 
The duodenum and the transverse colon are behind it. 

The gall-bladder acts as a reservoir for bile which it concentrates. 
It usually contains approximately 50 mL of bile which is released 
through the cystic and then common bile ducts into the duodenum in 
response to gall-bladder contraction induced by gut hormones. 

• Structure: the gall-bladder comprises a. fundus, a body and a neck 
(which opens into the cystic duct). 

• Blood supply: the arterial supply to the gall-bladder is derived from 
two sources: the cystic artery which is usually, but not always, a branch 
of the right hepatic artery, and small branches of the hepatic arteries 
which pass via the fossa in which the gall-bladder lies. The cystic artery 
represents the most significant source of arterial supply. There is, how- 
ever, no corresponding cystic vein but venous drainage occurs via 
small veins passing through the gall-bladder bed. 

The biliarytree 

The common hepatic duct is formed by the confluence of the right and 
left hepatic ducts in the porta hepatis. The common hepatic duct is 
joined by the cystic duct to form the common bile duct. This structure 
courses, sequentially, in the free edge of the lesser omentum, behind the 
first part of the duodenum and in the groove between the second part of 
the duodenum and the head of the pancreas. It ultimately opens at the 
papilla on the medial aspect of the second part of the duodenum. 

The common bile duct usually, but not always, joins with the main 
pancreatic duct (ofWirsung) (p. 47). 

Cholelithiasis 

Gallstones are composed of either cholesterol, bile pigment, or, more 
commonly, a mixture of these two constituents. Cholesterol stones form 
due to an altered composition of bile residting in the precipitation of 
cholesterol crystals. Most gallstones are asymptomatic; however, 
when they migrate down the biliary tree they can be responsible for a 
diverse array of complications such as: acute cholecystitis, biliary 
colic, cholangitis and pancreatitis. 



The liver, gall-bladder and biliary tree 45 



19 The pancreas and spleen 



Inferior vena cava 
Portal vein 



Coeliac artery 



Common bile duct 
Hepatic artery 
Right gastric artery 
Gastroduodenal artery 
Right gastroepiploic artery 



Superior 

pancreaticoduodenal artery 



Inferior 

pancreaticoduodenal artery 



Superior mesenteric 
artery and vein 




Fig.19.1 

The relations of the pancreas 



Right and left hepatic ducts 
Cystic duct - 
Cystic artery 

Neck 

Body 
Gall bladder 
(displaced) 

Fundus 

Accessory duct 
(of San tori ni) 

Duodenal papilla 
(of Vater) 



Uncinate process 



Right hepatic artery 




Pancreatic duct 
(of Wirsung) 



pancreas 



Fig.19.2 

The ducts of the pancreas and the biliary system 



Superior 
mesenteric vessels 



Left kidney 
and suprarenal 



Splenic 
artery 

Tail of 
pacreas 



Left gastric artery 



Splenic artery 



Inferior mesenteric 
artery and vein 




Fig.19.3 

The relations of the spleen 



Diaphragm 
Spleen 



Ribs 9, 
10 and 11 



Splenic flexure 
of colon 



46 Abdomen and pelvis 



The pancreas (Figs 19.1 and 19.2) 

The pancreas has a: head, neck, body and tail. It is a retroperitoneal 
organ which lies roughly along the transpyloric plane. The head is 
bound laterally by the curved duodenum and the tail extends to the 
hilum of the spleen in the lienorenal ligament. The superior mesenteric 
vessels pass behind the pancreas, then anteriorly, over the uncinate 
process and third part of the duodenum into the root of the small bowel 
mesentery. The inferior vena cava, aorta, coeliac plexus, left kidney 
(and its vessels) and the left adrenal gland are posterior pancreatic rela- 
tions. In addition, the portal vein is formed behind the pancreatic neck 
by the confluence of the splenic and superior mesenteric veins. The 
lesser sac and stomach are anterior pancreatic relations. 

• Structure: the main pancreatic duct (ofWirsimg) courses the length 
of the gland, ultimately draining pancreatic secretions into the ampulla 
of Voter, together with the common bile duct, and thence into the sec- 
ond part of the duodenum. An accessory duct (ofSantorini) drains the 
uncinate process of the pancreas, opening slightly proximal to the 
ampulla into the second part of the duodenum. 

• Blood supply: the pancreatic head receives its supply from the 
superior and inferior pancreaticoduodenal arteries. The splenic artery 
courses along the upper border of the body of the pancreas which it sup- 
plies by means of a large branch — the arteria pancreatica magna — and 
numerous smaller branches. 

• Function: the pancreas is a lobulated structure which performs both 
exocrine and endocrine functions. The exocrine secretory glands drain 
pancreatic juice into the pancreatic ducts and, from there, ultimately 
into the duodenum. The secretion is essential for the digestion and 
absorption of proteins, fats and carbohydrates. The endocrine pancreas 
is responsible for the production and secretion of glucagon and insulin, 
which take place in specialized cells of the islets of Langerhans. 

Acute pancreatitis 

The presence of gallstones and a history of excessive alcohol intake are 
the predominant associations for pancreatitis. The mechanism by 
which these aetiological factors result in pancreatic injury is unknown; 
however, they both appeal' to result in activation of pancreatic exocrine 
pro-enzymes with residtant autodigestion. Even today, the mortality 
rate for severe acute pancreatitis remains in the region of 20%. 



Tlie spleen (Fig. 19.3) 

The spleen is approximately the size of a clenched fist and lies directly 
below the left hemidiaphragm which, in addition to the pleura, separ- 
ates it from the overlying 9th, 10th and 1 1th ribs. 

• Peritoneal attachments: the splenic capsule is fibrous with peri- 
toneum adherent to its surface. The gastrosplenic and lienorenal liga- 
ments attach it to the stomach and kidney, respectively. The former 
ligament carries the short gastric and left gastroepiploic vessels to the 
fundus and greater curvature of the stomach, and the latter ligament 
carries the splenic vessels and tail of the pancreas towards the left 
kidney. 

• Blood supply: is from the splenic artery to the hilum of the spleen. 
Venous drainage is to the splenic vein, thence to the portal vein. 

• Structure: the spleen is a highly vascular reticulo-endothelial organ. 
It consists of a thin capsule from which trabeculae extend into the 
splenic pulp. In the spleen, the immunological centres, i.e. the lym- 
phoid follicles (the white pulp), are scattered throughout richly vascu- 
larized sinusoids (the red pulp). 

Splenectomy 

As the spleen is a highly vascular organ, any injury to it can be life- 
threatening. Under these circumstances splenectomy must be carried 
out urgently. The technique used differs slightly when the procedure is 
peiformed for emergency as opposed to elective indications, but the 
principles are similar. Splenectomy involves: ligature of the splenic 
vessels approaching the hilum (taking care not to injure the tail of the 
pancreas or colon); and dissection of the splenic pedicles — the gastro- 
splenic (including the short gastric vessels) and lienorenal ligaments. 
As the spleen is an important immunological organ, postsplenectomy 
patients are rendered immunocompromised to capsulated bacteria. 
The latter organisms (e.g. meningococcus, pneumococcus) require 
opsonization for elimination and splenic lymphoid follicles are the 
principal sites where this takes place. Hence, following splenectomy, 
all patients are routinely vaccinated against the capsulated bacteria, 
and children, who are the group most at risk of sepsis, are maintained 
on long-term antibiotic prophylaxis. 



The pancreas and spleen 47 



20 The posterior abdominal wall 



Transversus 



Quadratus 
lumborum 
Psoas major 

Genitofemoral 
nerve 




Fig.20.1 

The structures of the posterior abdominal wa 



Median sacral artery 



Papilla 

Minor 

calices 

Pyramid 



Interlobar 
artery 

Arcuate 
vessels 



Inferior phrenic artery 
Oesophagus 

Coeliac artery 

Superior mesenteric artery 

Iliohypogastric nerve 

Ilioinguinal nerve 

Gonadal artery 

Inferior mesenteric artery 

Femoral nerve 

Lateral cutaneous nerve of thigh 




Major calix 

Ureter 
Hilar fat 



Renal columns 



Fig.20.2 

A section through the right kidney. 

The small diagram shows how the renal columns 

represent the cortices of adjacent fused lobes 



Suprarenal 




intestine 



Fig.20.3 

The anterior relations of the kidneys 



Spleen 

Stomach 

Pancreas 

Colon 

Small 
intestine 




Diaphragm 
Outline of pleura 
12th rib 

Transversus abdominis 
Subcostal nerve 
llio-inguinal nerve 

Quadratus lumborum 
Psoas major 



Fig.20.4 

The posterior relations of the kidneys 



48 Abdomen and pelvis 



The structures of the posterior abdominal wall (Fig. 20. i) 

These include: 

• Muscles: including psoas major and quadratus lumborum (see 
Muscle index, p. 162). 

• The abdominal aorta and its branches: see p. 32. 

• The inferior vena cava (IVC) and its tributaries: see p. 35. 

• The kidneys. 

• The ureters. 

• The adrenal (suprarenal ) glands. 

• The lumbar sympathetic trunks and plexuses and the lumbar plexus 
(seep. 51). 

The kidneys (Fig. 20.2) 

• structure: the kidney has its own fibrous capsule and is surrounded 
by perinephric fat which, in turn, is enclosed by renal fascia. Each kid- 
ney is approximately 10-12 cm long and consists of an outer cortex, an 
inner medulla and a pelvis. 

The hilum of the kidney is situated medially and transmits from front 
to back the: renal vein, renal artery, ureteric pelvis as well as lymphatics 
and sympathetic vasomotor nerves. 

The renal pelvis divides into two or three major calices and these, in 
turn, divide into minor calices which receive urine from the medullary 
pyramids by way of the papillae. 

• Position: the kidneys lie in the retroperitoneum against the posterior 
abdominal wall. The right kidney lies approximately 1 cm lower than 
the left. 

• Relations: See Figs 20.3 and 20.4. 

• Blood supply: the renal arteries arise from the aorta at the level of 
L2. Together, the renal arteries direct 25% of the cardiac output 
towards the kidneys. Each renal artery divides into five segmental 
arteries at the hilum which, in turn, divide sequentially into lobar, 
interlobar, arcuate and cortical radial branches. The cortical radial 
branches give rise to the afferent arterioles which supply the glomeruli 
and go on to become efferent arterioles. The differential pressures 
between afferent and efferent arterioles lead to the production of an 
ultrafiltrate which then passes through, and is modified by, the nephron 
to produce urine. 

The right renal artery passes behind the IVC. The left renal vein is 
long as it courses in front of the aorta to drain into the IVC. 

• Lymphatic drainage: to the para-aortic lymph nodes. 

The ureter (Fig. 20.1) 

The ureter is considered in abdominal, pelvic and intravesical portions. 

• Structure: the ureter is approximately 20-30 cm long and courses 
from the hilum of the kidney to the bladder. It has a muscular wall and 
is lined by transitional epithelium. At operation it can be recognized by 
its peristalsis. 



• Course: from the renal pelvis at the hilum the course of the ureter can 
be summarized as follows: 

• It passes along the medial part of psoas major behind, but adherent 
to, the peritoneum. 

• It then crosses the common iliac bifurcation anterior to the 
sacro-iliac j oint and courses over the lateral wall of the pelvis to the 
ischial spine. 

• At the ischial spine the ureter passes forwards and medially to enter 
the bladder obliquely. The intravesical portion of the ureter is 
approximately 2 cm long and its passage through the bladder wall 
produces a sphincter-like effect. In the male the ureter is crossed 
superficially near its termination by the vas deferens. In the female 
the ureter passes above the lateral fornix of the vagina but below 
the broad ligament and uterine vessels. 

• Blood supply: as the ureter is an abdominal and pelvic structure it 
receives a blood supply from multiple sources: 

• The upper ureter — receives direct branches from the aorta, renal 
and gonadal arteries. 

• The lower ureter — receives branches of the internal iliac and in- 
ferior vesical arteries. 

Ureteric stones 

Most ureteric calculi arise for unknown reasons, although inadequate 
urinary drainage, the presence of infected urine, and hypercalcaemia 
are definite predisposing factors. The presence of an impacted ureteric 
stone is characterized by haematuria and agonizing colicky pain 
(ureteric colic), which classically radiates from loin to groin. Large 
impacted stones can lead to hydronephrosis and/or infection of the 
affected kidney and consequently need to be broken up or removed by 
interventional or open procedures. 

Adrenal (suprarenal) glands (Fig. 20.1) 

The adrenal glands comprise an outer cortex and inner medulla. The 
cortex is derived from mesoderm and is responsible for the production 
of steroid hormones (glucocorticoids, mineralocorticoids and sex 
steroids). The medulla is derived from ectoderm (neural crest) and acts 
as a part of the autonomic nervous system. It receives sympathetic 
preganglionic fibres from the greater splanchnic nerves which 
stimulate the medulla to secrete noradrenaline and adrenaline into the 
bloodstream. 

• Position: the adrenals are small glands which lie in the renal fascia 
on the upper poles of the kidneys. The right gland lies behind the right 
lobe of the liver and immediately posterolateral to the IVC. The left 
adrenal is anteriorly related to the lesser sac and stomach. 

• Blood supply: the phrenic, renal arteries and aorta all contribute 
branches to the adrenal glands. Venous drainage is on the right to the 
IVC and on the left to the left renal vein. 



The posterior abdominal wall 



21 The nerves of the abdomen 



Nerves 

Subcostal — 

Iliohypogastric 
Ilioinguinal 



Genitofemoral 

Lateral \ 

cutaneous 
of thigh 

Femoral 



Obturator 



Fig.21.1 

The lumbar plexus Lumbosacral trunk 




Medial arcuate 
ligament 



Grey and white rami 
(white rami on first 
two lumbar nerves only) 




Grey rami 
Fig.21.2 

The sympathetic system in the abdomen and pelvis 



Coeliac ganglia 



Suprarenal branch 



Cut psoas major 
Sympathetic trunk 
Lumbar sympathetic ganglia 
(usually4) 



Superior hypogastric plexus 
(presacral nerves) 



Inferior hypogastric plexus 
Pelvic sympathetic ganglia 



50 Abdomen and pelvis 



The lumbarplexus (Fig. 21.1) 

• The lumbar plexus is formed from the anterior primary rami of Ll-4. 
The trunks of the plexus lie within the substance of psoas major and, 
with the exceptions of the obturator and genitofemoral nerves, emerge 
at its lateral border. 

• The 12th intercostal nerve is also termed the subcostal nerve as it has 
no intercostal space but, instead, runs below the rib in the neurovascu- 
lar plane to supply the abdominal wall. 

• The iliohypogastric nerve is the main trunk of the 1 st lumbar nerve. It 
supplies the skin of the upper buttock, by way of a lateral cutaneous 
branch, and terminates by piercing the external oblique above the 
superficial inguinal ring where it supplies the overlying skin of the 
mons pubis. The ilioinguinal nerve is the collateral branch of the iliohy- 
pogastric. The ilioinguinal runs in the neurovascular plane of the 
abdominal wall to emerge through the superficial inguinal ring to pro- 
vide a cutaneous supply to the skin of the medial thigh, the root of the 
penis and anterior one third of the scrotum (or labium majus in the 
female). 

• The genitofemoral nerve (LI ,2) emerges from the anterior surface of 
psoas major. It courses inferiorly and divides into: a genital component 
that enters the spermatic cord and supplies the cremaster (in the male), 
and a femoral component that supplies the skin of the thigh overlying 
the femoral triangle. 

• The lateral cutaneous nerve of the thigh (L2,3), having emerged 
from the lateral border of psoas major, encircles the iliac fossa to pass 
under the inguinal ligament (p. 99). 

• The femoral nerve (L2-4, posterior division): see p. 99. 

• The obturator nerve (L2-4, anterior division): see p. 99. 

• A large part of L4 joins with L5 to contribute to the sacral plexus as 
the lumbosacral trunk. 



Lumbarsympathetic chain (Fig. 21.2) 

• Sympathetic supply: the lumbar sympathetic chain is a continuation 
of the thoracic sympathetic chain as it passes under the medial arcuate 
ligament of the diaphragm. The chain passes anterior to the lumbar ver- 
tebral bodies and usually carries four ganglia which send grey rami 
communicans to the lumbar spinal nerves. The upper two ganglia 
receive white rami from LI and L2. 

The lumbar sympathetic chain, the splanchnic nerves and the vagus 
contribute sympathetic and parasympathetic branches to plexuses 
(coeliac, superior mesenteric, renal and inferior mesenteric) around the 
abdominal aorta. In addition, other branches continue inferiorly to form 
the superior hypogastric plexus {presacral nerves) from where they 
branch into right and left inferior hypogastric plexuses. The latter also 
receive a parasympathetic supply from the pelvic splanchnic nerves. The 
branches from the inferior hypogastric plexuses are distributed to the 
pelvic viscera along the course and branches of the internal iliac artery. 

The coeliac ganglia are prominent and lie around the origins of the 
coeliac and superior mesenteric arteries. 

• Parasympathetic supply: to the pelvic viscera arises from the anter- 
ior primary rami of S2,3,4 — the pelvic splanchnic nerves. The latter 
parasympathetic supply reaches proximally as far as the junction 
between the hindgut and midgut on the transverse colon. 

Lumbar sympathectomy 

This procedure is performed in cases of severe peripheral vascular dis- 
ease of the lower limbs where vascular reconstructive surgery is not 
possible and skin necrosis is imminent. The operation involves excision 
of the 2nd to 4th lumbar ganglia with the intermediate chain. 



The nerves of the abdomen 51 



22 Surface anatomy of the abdomen 



Vertical line 



Costal margin 



Transpyloric plane 
Subcostal plane 
Level of umbilicus 
Transtubercular plane 



Fig.22.1 

The nine regions 
of the abdomen 




Fig.22.2 

McBurney's point and some 
of the structures that may be 
palpated in the abdomen 



Gall bladder 

(when distended) 
Lower pole of right 
kidney (sometimes) 
McBurney's point 
Inguinal ligament 

Deep inguinal ring 
and inferior 
epigastric artery 





Epigastrium 


Hypochondrium 




Umbilical 
• 


Lumbar 




Suprapubic 


Iliac fossa 




Liver, lower edge 

(sometimes) 

Linea alba 

Spleen, anterior notched 

margin (when grossly enlarged) 

Linea semilunaris 
(lateral border of rectus) 

Sigmoid colon 
(sometimes) 



External oblio^ue 
aponeurosis 

Internal obliq^ue 

Transversus 

Transversa I is fascia — i= 

Peritoneum 




Spermatic cord 
External spermatic fascia 

Internal spermatic fascia 
Cremasteric fascia and muscle 

Lower end of rectus abdominus 



Pubic tubercle 



Inferior Conjoint 

epigastric tendon 

artery 
Fig.22.3 

A horizontal section through the inguinal canal. Diagrammatic. 

(a) and (b) show the sites of indirect and direct herniae respectively 



52 Abdomen and pelvis 



Vertebral levels (Fig. 22. i) 

(In each case the lower border is referred to.) 

• T9: xiphoid process. 

• LI: the transpyloric plane (of Addison]. This horizontal plane passes 
approximately through the tip of the 9th costal cartilage, the pylorus, 
pancreatic neck, duodenojejunal flexure, the gall-bladder fundus and 
the hila of the kidneys. This plane also corresponds to the level at which 
the spinal cord terminates and the lateral edge of rectus abdominis 
crosses the costal margin. 

• L2: the subcostal plane. This plane corresponds to a line joining the 
lowest points of the thoracic cage — the lower margin of the 10th rib 
laterally. 

• L3: the level of the umbilicus (in a young slim person). 

• L4: the transtiihercidar plane . This corresponds to a line which joins 
the tubercles of the iliac crests. 

Lines of orientation 

Vertical lines: these are imaginary and most often used with the sub- 
costal and intertubercular planes, for purposes of description, to subdi- 
vide the abdomen into nine regions (Fig. 22.1). They pass vertically, on 
either side, through the point halfway between the anterior superior 
iliac spine and the pubic tubercle. More commonly used, for descrip- 
tion of pain location, are quadrants. The latter are imaginary lines aris- 
ing by the bisection of the umbilicus by vertical and horizontal lines. 

Surface markings of the abdominal wall 

• The costal margin (Fig. 22.1) is the inferior margin of the thoracic 
cage. It includes the costal cartilages anteriorly, the 7th-10th ribs later- 
ally and the cartilages of the 1 1th and 12th ribs posteriorly. 

• The symphysis pubis is an easily palpable secondary cartilaginous 
joint which lies between the pubic bones in the midline. The pubic 
tubercle is an important landmark and is identifiable on the superior 
surface of the pubis. 

• The inguinal ligament (Figs 11.1 and 22.2) is attached laterally to the 
anterior superior iliac spine and medially to the pubic tubercle. 

• The superficial inguinal ring (see Fig. 11.1) is a triangular-shaped 
defect in the external oblique aponeurosis. It is situated above and 
medial to the pubic tubercle. 

• The spermatic cord can be felt passing medial to the pubic tubercle 
and descending into the scrotum. 

• The deep inguinal ring (Fig. 22.3) lies halfway along a line from the 
anterior superior iliac spine to the pubic tubercle. 

• The //«ea a/^a (see Fig. 11.1) is formed by the fusion of the aponeu- 
roses of the muscles of the anterior abdominal wall. It extends as a de- 
pression in the midline from the xiphoid process to the symphysis pubis. 



• The linea semilunaris is the lateral edge of the rectus abdominis 
muscle. It crosses the costal margin at the tip of the 9th costal cartilage. 

Inguinal herniae (Figs 22.3 and 52. i) 

• Indirect inguinal herniae: arise as a result of persistence of the pro- 
cessus vaginalis of the embryo. Abdominal contents bulge through the 
deep inguinal ring, into the canal, and eventually into the scrotum. This 
hernia can be controlled by digital pressure over the deep ring. 

• Direct inguinal herniae: arise as a result of weakness in the poster- 
ior wall of the inguinal canal. This hernia cannot be controlled by 
digital pressure over the deep ring and only rarely does the hernia pass 
into the scrotum . 

The clinical distinction between direct and indirect inguinal hernias 
can be difficult. At operation, however, the relation of the hernial neck 
to the inferior epigastric artery defines the hernia type, i.e. the neck of 
the sac of an indirect hernia lies lateral to the artery whereas that of a 
direct type always lies medial to it. 

Surface markings of the abdominal viscera (Fig. 22.2) 

• Liver: the lower border of the liver is usually just palpable on deep 
inspiration in slim individuals. The upper border follows the undersur- 
face of the diaphragm and reaches a level just below the nipple on each 
side. 

• Spleen: this organ lies below the left hemidiaphragm deep to the 9th, 
10th and 11th ribs posteriorly. The anterior notch reaches the mid- 
axillary line anteriorly. 

• Gall-bladder: the fundus of the gall-bladder lies in the transpyloric 
plane (LI). The surface marking corresponds to a point where the lat- 
eral border of rectus abdominis {linea semilimaris) crosses the costal 
margin. 

• Pancreas: the pancreatic neck lies on the level of the transpyloric 
plane (LI). The pancreatic head lies to the right and below the neck 
whereas the body and tail pass upwards and to the left. 

• Aorta: the aorta bifurcates to the left of the midline at the level of L4. 

• Kidneys: the kidney hila lie on the level of the transpyloric plane 
(LI). The lower pole of the right kidney usually extends 3 cm below the 
level of the left and is often palpable in slim subjects. 

• Appendix: McBurney's point represents the surface marking for the 
base of the appendix. This point lies one third of the way along a line 
joining the anterior superior iliac spine and the umbilicus. McBurney's 
point is important surgically as it represents the usual site of maximal 
tenderness in appendicitis and also serves as the central point for the 
incision made when performing an appendicectomy. 

• Bladder: in adults the bladder is a pelvic organ and can be palpated 
above the symphysis pubis only when full or enlarged. 



Surface anatomy of the abdomen 53 



23 The pelvis I— the bony and ligamentous pelvis 




Inferior q\utea\ line 

Anterior superior 
iliac spine 
Anterior inferior 
iliac spine 

Acetabulum 
Obturator foramen 
Pubic tubercle 
Pubic crest 

Body of pubis 
Inferior ramus 

Fig.23.1 

The lateral surface of the left hip bone 



lac crest 

Anterior gluteal line 

Posterior superior 
iliac spine 

Posterior gluteal line 
Greater sciatic notch 

Spine of ischium 
Lesser sciatic notch 

Ischial tuberosity 

Ramus of ischium 




Iliac fossa 



Auricular 
surface 



lliopectineal 
line 
Pubic 
tubercle 

Pubic 
symphysis 



Fig.23.2 

The medial surface of the left hip bone 



Spinous tubercle 




Superior articular 

facet 

Ala 

Articular tubercle 

Posterior sacral 

foramen 

Auricular surface 

Transverse tubercle 



Sacral hiatus 



Fig.23.3 

The posterior surface of the sacrum 



Body weight 




Pelvic brim 
True pelvis 



Greater sciatic foramen 

Sacrospinous ligament 
Lesser sciatic foramen 
Sacrotuberous ligament 



Fig.23.4 

The sacrospinous and sacrotuberous ligaments resist 
rotation of the sacrum due to the body weight 



Fig.23.5 

The male pelvic floor from above. 
The blue line represents the origin 
of levator ani from the obturator 
fascia 



Sacral nerves — 

Spine of ischium 
Puborectalis 



Prostate 

Anterior edge 
of levator ani 




Piriformis 
Coccygeus 
Ischiococcygeus 
Recto-anal junction 

Perineal body 
Obturator fascia 
Obturator internus 
Levator prostatae 



54 Abdomen and pelvis 



The pelvis is bounded posteriorly by the sacrum and coccyx and antero- 
laterally by the innominate bones. 

Os innominatum (hip bone) (Figs 23.1 and 23.2) 

This bone comprises three component parts, the: ilium, ischium and 
pubis. By adulthood the constituent bones have fused together at the 
acetabulum. Posteriorly each hip bone articulates with the sacrum at the 
sacro-iliac joint (a synovial joint). 

• Ilium: the iliac crest forms the upper border of the bone. It runs back- 
wards from the anterior superior iliac spine to the posterior superior 
iliac spine. Below each of these bony landmarks are the corresponding 
inferior spines. The outer surface of the ilium is termed the gluteal sur- 
face as it is where the gluteal muscles are attached. The inferior, anter- 
ior and posterior gluteal lines demarcate the bony attachments of the 
glutei. The inner surface of the ilium is smooth and hollowed out to 
form the iliac fossa. It gives attachment to the iliacus muscle. The 
auricular surface of the ilium articulates with the sacrum at the sacro- 
iliac joints (synovial joints). Fo.v/er/or, interosseous and anterior sacro- 
iliac ligaments strengthen the sacro-iliac joints. The iliopectineal line 
courses anteriorly on the inner surface of the ilium from the auricular 
surface to the pubis. It forms the lateral margin of the pelvic brim (see 
below). 

• Ischium: comprises a spine on its posterior part which demarcates 
the greater (above) and lesser sciatic (below) notches. The ischial 
tuberosity is a thickening on the lower part of the body of the ischium 
which bears weight in the sitting position. The ischial ramus projects 
forwards from the tuberosity to meet and fuse with the inferior pubic 
ramus. 

• Pubis: comprises a body and superior and inferior pubic rami. It 
articulates with the pubic bone of the other side at the symphysis pubis 
(a secondary cartilaginous joint). The superior surface of the body 
bears thcpubic crest and thepubic tubercle (Fig. 23.1). 

The obturator foramen is a large opening bounded by the rami of the 
pubis and ischium. 

The sacrum and coccyx (Fig. 23.3) 

• The sacrum comprises five fused vertebrae. The anterior and lateral 
aspects of the sacrum are termed the central and lateral masses, respect- 
ively. The upper anterior part is termed the sacral promontory. Four 
anterior sacral foramina on each side transmit the upper four sacral 
anterior primary rami. Posteriorly, the fused pedicles and laminae form 
the sacral canal representing a continuation of the vertebral canal. 
Inferiorly, the canal terminates at the sacral hiatus. Sacral cornua 
bound the hiatus inferiorly on either side. The subarachnoid space ter- 
minates at the level of S2. The sacrum is tilted anteriorly to form the 
lumbosacral angle with the lumbar vertebra. 

• The coccyx articulates superiorly with the sacrum. It comprises 
between three and five fused rudimentary vertebrae. 

The obturator membrane 

The obturator membrane is a sheet of fibrous tissue which covers the 
obturator foramen with the exception of a small area for the passage of 
the obturator nerve and vessels which traverse the canal to pass from 
the pelvis to gain access to the thigh. 



The pelvic cavity 

The pelvic brim (also termed the pelvic inlet) separates the pelvis into 
the false pelvis (above) and the true pelvis (below). The brim is formed 
by the sacral promontory behind, the iliopectineal lines laterally and the 
symphysis pubis anteriorly. The pelvic outlet is bounded by the coccyx 
behind, the ischial tuberosities laterally and the pubic arch anteriorly. 
The true pelvis (pelvic cavity) lies between the inlet and outlet. The 
false pelvis is best considered as part of the abdominal cavity. 

The ligaments of the pelvis (Fig. 23.4) 

These include the: 

• Sacrotuberous ligament: extends from the lateral part of the sacrum 
and coccyx to the ischial tuberosity. 

• Sacrospinous ligament: extends from the lateral part of the sacrum 
and coccyx to the ischial spine. 

The above ligaments, together with the sacro-iliac ligaments, bind 
the sacrum and coccyx to the os and prevent excessive movement at the 
sacro-iliac joints. In addition, these ligaments create the greater and 
lesser sciatic foramina with the greater and lesser sciatic notches. 

The pelvic floor (Fig. 23.5) 

The pelvic floor muscles: support the viscera; produce a sphincter 
action on the rectum and vagina and help to produce increases in intra- 
abdominal pressure during straining. The rectum, urethra and vagina 
(in the female) traverse the pelvic floor to gain access to the exterior. 
The levator ani and coccygeus muscles form the pelvic floor, while piri- 
formis covers the front of the sacrum. 

• Levator ani: arises from the posterior aspect of the pubis, the fascia 
overlying obturator internus on the side wall of the pelvis and the 
ischial spine. From this broad origin fibres sweep backwards towards 
the midline as follows: 

• Anterior fibres {sphincter vaginae or levator prostatae) — these 
fibres surround the vagina in the female (prostate in the male) and 
insert into the perineal body. The latter structure is a flbromuscular 
node which lies anterior to the anal canal. 

• Intermediate fibres (puborectali.'i)— these fibres surround the 
anorectal junction and also insert into the deep part of the anal 
sphincter. They provide an important voluntary sphincter action at 
the anorectal junction. 

• Posterior fibres (iliococcygeus)— these fibres insert into the lateral 
aspect of the coccyx and a median fibrous raphe (the anococcygeal 
body). 

• Coccygeus: arises from the ischial spine and inserts into the lower 
sacrum and coccyx. 

Sex differences in the pelvis 

The female pelvis differs from that of the male for the purpose of child- 
bearing. The major sex differences include: 

1 The pelvic inlet is oval in the female. In the male the sacral promon- 
tory is prominent, producing a heart-shaped inlet. 

2 The pelvic outlet is wider in females as the ischial tuberosities are 
everted. 

3 The pelvic cavity is more spacious in the female than in the male. 

4 The false pelvis is shallow in the female. 

5 The pubic arch (the angle between the inferior pubic rami) is wider 
and more rounded in the female when compared with that of the male. 



The pelvis I — the bony and ligamentous pelvis 55 



24 The pelvis II— the contents of the pelvis 




Bladder 



Fig. 24.1 

The ligaments of the uterus 



Uterosacral 
ligament 
Endopelvic 
fascia 

Cardinal 
ligaments 



Pubocervical 
ligament 



External 

iliac vessels 

Round 

ligament 

Ligament 

of the ovary 

Uterine tube — 

Round ligament 
Uterine artery 

Cut edge of — 
broad ligament 

Ureter 




Internal iliac 

vessels 

Infundibulopelvic 

ligament 

Ureter 

Fimbriated end 
of tube 
Ovary 

Mesovarium 



Fig. 24.2 

The broad ligamentcutoff close to the uterus 



Transverse 
cervical ligament 



Ureter 



Deep circumflex 
iliac artery 



External iliac artery 



Inferior epigastric artery 



Ductus deferens 

Obliterated umbilical artery 

Obturator artery 



Attachment of levator ani 



Fig. 24.3 

The pelvic arteries in the male 




Obturator nerve 
Iliolumbar artery 
Superior gluteal artery 

Lateral sacral artery 
Inferior gluteal artery 

Tendon of obturator internus 

Inferior vesical and middle 
rectal arteries 

Internal pudendal artery 



56 Abdomen and pelvis 



Pelvic fascia (Fig. 24. i) 

The pelvic fascia is the term given to the connective tissue that lines the 
pelvis covering levator ani and obturator internus. It is continuous with 
the fascial layers of the abdominal wall above and the perineum below. 
Endopelvic fascia is the term given to the loose connective tissue that 
covers the pelvic viscera. The endopelvic fascia is condensed into fas- 
cial ligaments which act as supports for the cervix and vagina. These 
ligaments include the: 

• Cardinal (Mackenrodt's) ligaments: pass laterally from the cervix 
and upper vagina to the pelvic side walls. 

• Utero-sacral ligaments: pass backwards from the cervix and va- 
ginal fornices to the fascia overlying the sacro-iliac joints. 

• Pubocervical ligaments: extend anteriorly from the cardinal liga- 
ments to the pubis (puboprostatic in the male). 

• Pubovesical ligaments: from the back of the symphysis pubis to the 
bladder neck. 

Ttie broad and round ligaments (Fig. 24.2) 

• Broad ligament: is a double fold of peritoneum which hangs 
between the lateral aspect of the uterus and the pelvic side walls. The 
ureter passes forwards under this ligament, but above and lateral to the 
lateral fornix of the vagina, to gain access to the bladder. The broad liga- 
ment contains the following structures: 

• Fallopian tube. 

• Ovary. 

• Ovarian ligament. 

• Round ligament (see below). 

• Uterine and ovarian vessels. 

• Nerves and lymphatics. 

• Round ligament: is a cord-like fibromuscular structure which is the 
female equivalent of the gubernaculum in the male. It passes from the 
lateral angle of the uterus to the labium majus by coursing in the broad 
ligament and then through the inguinal canal (p. 30). 

Arteries of the pelvis (Fig. 24.3) 

• Common iliac arteries: arise from the aortic bifurcation to the left of 
the midline at the level of the umbilicus. These arteries, in turn, bifur- 
cate into external and internal iliac branches anterior to the sacro-iliac 
joints on either side. 

• External iliac artery: courses from its origin (described above) to 
become the femoral artery as it passes under the inguinal ligament at 
the mid-inguinal point. The external iliac artery gives rise to branches 
which supply the anterior abdominal wall. These include the: deep cir- 



cuinflex iliac artery and inferior epigastric artery. The latter branch 
gains access to the rectus sheath, which it supplies, and eventually 
anastomoses with the superior epigastric artery. 

• Internal iliac artery: courses from its origin (described above) 
to divide into anterior and posterior trunks at the level of the greater 
sciatic foramen. 

Branches of the anteriortrunk 

• Obturator artery: passes with the obturator nerve through the obtur- 
ator canal to enter the thigh. 

• Umbilical artery: although the distal part is obliterated the proximal 
part is patent and gives rise to the superior vesical artery which con- 
tributes a supply to the bladder. 

• Inferior vesical artery: as well as contributing a supply to the blad- 
der it also gives off a branch to the vas deferens (in the male). 

• Middle rectal artery: anastomoses with the superior and inferior 
rectal arteries to supply the rectum. 

• Internal pudendal artery: is the predominant supply to the per- 
ineum. It exits the pelvis briefly through the greater sciatic foramen but 
then re-enters below piriformis through the lesser sciatic foramen to 
enter the pudendal canal together with the pudendal nerve. 

• Uterine artery: passes medially on the pelvic floor and then over the 
ureter and lateral fornix of the vagina to ascend the lateral aspect of the 
uterus between the layers of the broad ligament. 

• Inferior gluteal artery: passes out of the pelvis through the greater 
sciatic foramen to the gluteal region which it supplies. 

• Vaginal artery. 

Branches of the posteriortrunk 

• Superior gluteal artery: contributes a supply to the gluteal muscles. 
It leaves the pelvis through the greater sciatic foramen. 

• Ilio-lumbar artery. 

• Lateral sacral artery. 

Veins of the pelvis 

The right and left common iliac veins join to form the inferior vena 
cava behind the right common iliac artery but anterolateral to the body 
of L5. The overall arrangement of pelvic venous drainage reciprocates 
that of the arterial supply. 

Nerves of the pelvis 

Sacral plexus (see p. 100). 



The pelvis II— the contents of the pelvis 57 



25 The perineum 



Dorsal vein 

Corpus cavernosum 

Corpus spongiosum 
with uretlira 



Penile 



Crus 
Bulb 



Perineal membrane 
Perineal body 



Fig.25.1 

The male perineum 




Testicular 
artery 



Vas deferens 



Tunica 
vaginalis 



Muscles 

Ischiocavernosus 
Bulbospongiosus 

Superficial transverse 
perineal muscle 

Levator ani 

External sphincter ani 
Gluteus maximus 



Crus clitoris - 
Glans clitoris 

Urethra 

Bulb 




Vagina 

Bartholin's gland 
Perineal membrane 
Ischial tuberosity 

Perineal body 



Fig.25.2 

The female perineum 



Pampiniform 
plexus 

Epididymis 



Testis 




Muscles 

Bulbospongiosus 

Ischiocavernosus 

Superficial transverse 
perineal muscle 

External anal sphincter 

Levator ani 

Gluteus maximus 



Fig.25.3 

The testis and epididymis 



58 Abdomen and pelvis 



The perineum lies below the pelvic diaphragm. It forms a diamond- 
shaped area when viewed from below that can be divided into an anter- 
ior urogenital region and a posterior anal region by a line joining the 
ischial tuberosities horizontally. 

Anal region (Figs 25.1 and 17.2) 

The anal region contains the anal canal and ischiorectal fossae. 

• Anal canal: is described earlier (p. 43). 

• Anal sphincter: comprises external and internal sphincter compon- 
ents. The internal anal sphincter is a continuation of the inner circular 
smooth muscle of the rectum. The external anal sphincter is a skeletal 
muscular tube which, at its rectal end, blends with puborectalis to form 
an area of palpable thickening termed the anorectal ring. The compet- 
ence of the latter is fundamental to anal continence. 

• Ischiorectal fossae: lie on either side of the anal canal. The medial 
and lateral walls of the ischiorectal fossa are the levator ani and anal 
canal and the obturator internus, respectively. The fossae are filled with 
fat. The anococcygeal body separates the fossae posteriorly; however, 
infection in one fossa can spread anteriorly to the contralateral fossa 
forming a horseshoe abscess. The pudendal (Alcock'sj canal is a sheath 
in the lateral wall of the ischiorectal fossa. It conveys the pudendal 
nerve and internal pudendal vessels from the lesser sciatic notch to the 
deep perineal pouch (see below). The inferior rectal branches of the 
pudendal nerve and internal pudendal vessels course transversely 
across the fossa to reach the anus. 

Urogenital region 

The urogenital region is triangular in shape. The perineal membrane is 
a strong fascial layer that is attached to the sides of the urogenital tri- 
angle. In the male it is pierced by the urethra and, in females, by the 
urethra and vagina. 

(a) In the female (Fig. 25.2) 

• Vulva: is the term given to the female external genitalia. The mons 
pubis is the fatty protuberance overlying the pubic symphysis and 
pubic bones. The labia majora are fatty hair-bearing lips that extend 
posteriorly from the mons. The labia minora lie internal to the labia 
majora and unite posteriorly at the fourchette. Anteriorly, the labia 
minora form the prepuce and split to enclose the clitoris. The clitoris 
corresponds to the penis in the male. It has a similar structure in that it is 
made up of three masses of erectile tissue: the bulb (corresponding to 
the penile bulb) and right and left crura covered by similar but smaller 
muscles than those in the male. As in the male, these form the contents 
of the superficial perineal pouch. The deep perineal pouch, however, 
contains the vagina as well as part of the urethra and sphincter urethrae 
and internal pudendal vessels. The vestibule is the area enclosed by the 
labia minora and contains the urethral and vaginal orifices. Deep to the 
posterior aspect of the labia majoris lie Bartholin's glands — a pair of 
mucus-secreting glands that drain anteriorly. They are not palpable in 
health but can become grossly inflamed when infected. 

• Urethra: is short in the female (3-4 cm). This factor contributes 
towards the predisposition to urinary tract infection due to upward 
spread of bowel organisms. The urethra extends from the bladder neck 
to the external meatus. The meatus lies between the clitoris and vagina. 

• Vagina: measures approximately 8-12 cm in length. It is a muscular 
tube that passes upwards and backwards from the vaginal orifice. The 
cervix projects into the upper anterior aspect of the vagina creating 
fornices anteriorly, posteriorly and laterally. Lymph from the upper 
vagina drains into the internal and external iliac nodes. Lymph from the 



lower vagina drains to the superficial inguinal nodes. The blood supply 
to the vagina is from the vaginal artery (branch of the internal iliac 
artery) and the vaginal branch of the uterine artery. 

(b) In the male (Fig. 25.1) 

The external urethral sphincter (striated muscle) lies deep to the per- 
ineal membrane within a fascial capsule termed the deep perineal 
pouch. In addition to the sphincter, two glands of Cowper are also 
contained within the deep pouch. The ducts from these glands pass 
forwards to drain into the bulbous urethra. Inferior to the perineal mem- 
brane is the superficial perineal pouch which contains the: 

• Superficial transverse perineal muscles: run from the perineal 
body to the ischial ramus. 

• Bulbo-spongiosus muscle: covers the corpus spongiosum. The lat- 
ter structure covers the spongy urethra. 

• Ischio-cavernosus muscle: arises on each side from the ischial 
ramus to cover the corpus cavernosum. It is the engorgement of venous 
sinuses within these cavernosa that generate and maintain an erection. 

Hence, the penile root comprises a well-vascularized bulb and two 
crura which are supplied by branches of the internal pudendal artery. 
The erectile penile tissue is enclosed within a tubular fascial sheath. At 
the distal end of the penis the corpus spongiosum expands to form the 
glans penis. On the tip of the glans the urethra opens as the external 
urethral meatus. The foreskin is attached to the glans below the meatus 
by a fold of skin— the/re ;7;(///m. 

The scrotum 

The skin of the scrotum is thin, rugose and contains many sebaceous 
glands. A longitudinal median raphe is visible in the midline. Beneath the 
skin lies a thin layer of involuntary dartos muscle. The terminal spermatic 
cords, the testes and their epididymes are contained within the scrotum. 

Testis and epididymis (Fig. 25.3) 

The testes are responsible for spermatogenesis. Their descent to an extra- 
abdominal position favours optimal spermatogenesis as the ambient 
scrotal temperature is approximately 3°C lower than body temperature. 

• Structure: the testis is divided internally by a series of septa into 
approximately 200 lobules. Each lobule contains 1-3 seminiferous 
tubules which anastomose into a plexus termed the rete testis. Each 
tubule is coiled when in situ, but when extended measures approxim- 
ately 60 cm. Efferent ducts connect the rete testis to the epididymal 
head. They serve to transmit sperm from the testicle to the epididymis. 

• The tunica vaginalis, derived from the peritoneum, is a double 
covering into which the testis is invaginated. 

• The tunica albuginea is a tough fibrous capsule that covers the testis. 

• The epididymis lies along the posterolateral and superior borders of 
the testicle. The tunica vaginalis covers the epididymis with the 
exception of the posterior border. 

• The upper poles of both the testis and epididymis bear an appendix 
testis and appendix epididymis {hydatid ofMorgagni), respectively. 

• Blood supply: is from the testicular artery (a branch of the abdom- 
inal aorta, p. 32). Venous drainage from the testicle is to the pampini- 
form plexus of veins. The latter plexus lies within the spermatic cord 
but coalesces to form a single vein at the internal ring. The left testicu- 
lar vein drains to the left renal vein whereas the right testicular vein 
drains directly to the inferior vena cava. 

• Lymphatic drainage: is to the para-aortic lymph nodes. 

• Nerve supply: is from T 1 sympathetic fibres via the renal and aortic 
plexuses. 



The perineum 59 



26 The pelvic viscera 



Uterovesical 
pouch 

Bladder 
Urethra 
Vagina 
Vestibule 

Perineal body 




Rectum 

Recto-uterine pouch 
Posterior fornix 
of vagina 
Cervix of uterus 
Sphincterani 
extern us 
Anal canal 



Bladder 

Suspensory 

ligament 

Prostatic 

urethra 

Membranous 

urethra 



Fig.26.1 

Sagittal sections through the male and female pelves 



Prostate 



Anal canal 

Perineal 
body 



Lateral 
cornu 



Ovarian 
artery 

Uterine 
artery 

Ureter 



Ureter 



Trigone 



Prostate 




Sphincter 
urethrae 



Ureter 

Ductus 

deferens 

Ampulla 

Seminal 

vesicle 

Prostate 

Fig.26.2 

The bladder and prostate 




Fallopian tube 
Body 



Vaginal artery 
Vagina 



Internal OS 
Supravaginal cervix 
Cervical canal 
Intravaginal cervix 
Lateral fornix 
External OS 



Fig.26.3 

A vertical section through the uterus and vagina. 
Note the relation of the uterine artery to the ureter 



Contents of the pelvic cavity (see Fig. 24. i) 

• Sigmoid colon: see p. 43. 

• Rectum: see p. 43. 

• Ureters: seep. 49. 

• Bladder (Fig. 26.2): see below. 

Bladder 

In adults the bladder is a pelvic organ. It lies behind the pubis and is 
covered superiorly by peritoneum. It acts as a receptacle for urine and 
has a capacity of approximately 500 mL. 



• Structure: the bladder is pyramidal in shape. The apex of the pyra- 
mid points forwards and from it a fibrous cord, the urachus, passes 
upwards to the umbilicus as the median umbilical ligament. The base 
(posterior surface) is triangular. In the male, the seminal vesicles lie on 
the outer posterior surface of the bladder and are separated by the vas 
deferens. The rectum lies behind. In the female, the vagina intervenes 
between the bladder and rectum. The inferolateral surfaces are related 
inferiorly to the pelvic floor and anteriorly to the retropubic fat pad and 
pubic bones. The bladder neck fuses with the prostate in the male 
whereas it lies directly on the pelvic fascia in the female. The pelvic 



60 Abdomen and pelvis 



fascia is thickened in the form of the puboprostatic ligaments (male) 
and pubovesical ligaments to hold the bladder neck in position. The 
mucous membrane of the bladder is thrown into folds when the bladder 
is empty with the exception of the membrane overlying the base 
(termed the trigone) which is smooth. The superior angles of the 
trigone mark the openings of the ureteric orifices. A muscular eleva- 
tion, the interureteric ridge, runs between the ureteric orifices. The 
inferior angle of the trigone corresponds to the internal urethral mea- 
tus. The muscle coat of the bladder is composed of a triple layer of tra- 
beculated smooth muscle known as the detrusor (muscle). The detrusor 
is thickened at the bladder neck to form the sphincter vesicae. 

• Blood supply: is from the superior and inferior vesical arteries 
(branches of the internal iliac artery, p. 57). The vesical veins coalesce 
around the bladder to form a plexus that drains into the internal iliac 
vein. 

• Lymph drainage: is to the para-aortic nodes. 

• Nerve supply: motor input to the detrusor muscle is from efferent 
parasympathetic fibres from S2-4. Fibres from the same source convey 
inhibitory fibres to the internal sphincter so that co-ordinated micturi- 
tion can occur. Conversely, sympathetic efferent fibres inhibit the 
detrusor and stimulate the sphincter. 

The male pelvic organs 

The prostate (Fig. 26.2) 

In health the prostate is approximately the size of a walnut. It surrounds 
the prostatic urethra and lies between the bladder neck and the urogen- 
ital diaphragm. The apex of the prostate rests on the external urethral 
sphincter of the bladder. It is related anteriorly to the pubic symphysis 
but separated from it by extraperitoneal fat in the retropubic space 
{cave ofRetzius). Posteriorly, the prostate is separated from the rectum 
by thefascia ofDenonvilliers. 

• Structure: the prostate comprises anterior, posterior, middle and lat- 
eral lobes. On rectal examination a posterior median groove can be pal- 
pated between the lateral lobes. The prostatic lobes contain numerous 
glands producing an alkaline secretion which is added to the seminal 
fluid at ejaculation. The prostatic glands open into the prostatic sinus. 
The ejaculatory ducts, which drain both the seminal vesicles and the 
vas, enter the upper part of the prostate and then the prostatic urethra at 
the verumontanum. 

• Blood supply: is from the inferior vesical artery (branch of the inter- 
nal iliac artery, p. 57). A prostatic plexus of veins is situated between 
the prostatic capsule and the outer fibrous sheath. The plexus receives 
the dorsal vein of the penis and drains into the internal iliac veins. 

The vas deferens 

The vas deferens conveys sperm from the epididymis to the ejaculatory 
duct from which it can be passed to the urethra. The vas arises from the 
tail of the epididymis and traverses the inguinal canal to the deep ring, 
passes downwards on the lateral wall of the pelvis almost to the ischial 
tuberosity and turns medially to reach the base of the bladder where it 
joins with the duct of the seminal vesicle to form the ejaculatory duct. 

The seminal vesicles (Fig. 26.2) 

The seminal vesicles consist of lobulated tubes which lie extraperi- 

toneally on the bladder base lateral to the vas deferens. 

The urethra (Fig. 26.1) 

The male urethra is approximately 20 cm long (4 cm in the female). It 

is considered in three parts: 



• Prostatic urethra (3 cm): bears a longitudinal elevation {urethral 
crest) on its posterior wall. On either side of the crest a shallow depres- 
sion, the. prostatic sinus, marks the drainage point for 15-20 prostatic 
ducts. The prostatic utricle is a 5 mm blind ending tract which opens 
into an eminence in the middle of the crest— the verumontanum. The 
ejaculatory ducts open on either side of the utricle. 

• Membranous urethra (2 cm): lies in the urogenital diaphragm and 
is surrounded by the external urethral sphincter {sphincter urethrae). 

• Penile urethra (15 cm): traverses the corpus spongiosum of the 
penis (see perineum, p. 59) to the external urethral meatus. 

The female pelvic organs 

The vagina 

See perineum, p. 59. 

The uterus and fallopian tubes (Fig. 26.3) 

• Structure: the uterus measures approximately 8 cm in length in the 
nuUiparous female. It comprises a: fundus (part lying above the 
entrance of the fallopian tubes), body and cervix. The cervix is sunken 
into the anterior wall of the vagina and is consequently divided into 
supravaginal and vaginal parts. The internal cavity of the cervix com- 
municates with the cavity of the body at the internal os and with the 
vagina at the external os. The fallopian tubes lie in the free edges of the 
broad ligaments and serve to transmit ova from the ovary to the cornua 
of the uterus. They comprise an: infundihiditm, ampulla, isthmus and 
interstitial part. The uterus is made up of a thick muscular wall 
{myometrium) and lined by a mucous membrane {endometrium). The 
endometrium undergoes massive cyclical change during menstruation. 

• Relations: the uterus and cervix are related to the uterovesical pouch 
and superior surface of the bladder anteriorly. The recto-uterine pouch 
(of Douglas), which extends down as far as the posterior fornix of the 
vagina, is a posterior relation. The broad ligament is the main lateral 
relation of the uterus. 

• Position: in the majority, the uterus is anteverted, i.e. the axis of the 
cervix is bent forward on the axis of the vagina. In some women the 
uterus is retroverted. 

• Blood supply: is predominantly from the uterine artery (a branch of 
the internal iliac artery, p. 57). It runs in the broad ligament and, at the 
level of the internal os, crosses the ureter at right angles to reach, and 
supply, the uterus before anastomosing with the ovarian artery (a 
branch of the abdominal aorta, p. 32). 

• Lymph drainage: lymphatics from the fundus accompany the ovar- 
ian artery and drain into the para-aortic nodes. Lymphatics from the 
body and cervix drain to the internal and external iliac lymph nodes. 

The ovary 

Each ovary contains a number of primordial follicles which develop in 
early fetal life and await full development into ova. In addition to the 
production of ova, the ovaries are also responsible for the production of 
sex hormones. Each ovary is surrounded by a fibrous capsule, the 
tunica albuginea. 

• Attachments: the ovary lies next to the pelvic side wall and is 
secured in this position by two structures: the broad ligament which 
attaches the ovary posteriorly by the mesovarium; and the ovarian liga- 
ment which secures the ovary to the cornu of the uterus. 

• Blood supply: is from the ovarian artery (a branch of the abdominal 
aorta). Venous drainage is to the inferior vena cava on the right and to 
the left renal vein on the left. 

• Lymphatic drainage: is to the para-aortic nodes. 



The pelvic viscera 6 1 



27 The osteology of the upper limb 



Medial (sternal) end 




Tubercle for costo- 
clavicular ligament 

Fig.27.1 

The upper and lower surfaces of the left clavicle 



Facet for acromion 
"Trapezoid line 

Conoid tubercule 




Fig.27.2 

X-ray of a fractured clavicle 



The clavicle (Fig.27.1) 

• The clavicle is the first bone to ossify in the fetus (6 weeks). 

• It develops in membrane and not in cartilage. 

• It is subcutaneous throughout its length and transmits forces from the 
arm to the axial skeleton. 

• The medial two-thirds are circular in cross-section and curved con- 
vex forwards. The lateral third is flat and curved convex backwards. 

• The clavicle articulates medially with the sternum and 1st costal car- 
tilage at the sternoclavicular joint. The clavicle is also attached medi- 
ally to the 1st rib by strong costoclavicular ligaments and to the 
sternum by sternoclavicular ligaments. 



• The clavicle articulates laterally with the acromion process of the 
scapula — the acromioclavicular joint. The coracoclavicular ligaments 
secure the clavicle inferolaterally to the coracoid process of the 
scapula. This ligament has two components — the conoid and trapezoid 
ligaments which are attached to the conoid tubercle and trapezoid line 
of the clavicle, respectively. 

• The clavicle is the most commonly fractured bone in the body. The 
weakest point of the bone is the junction of the middle and outer thirds 
(Fig. 27.2). 



62 Upper limb 



Spinoglenoid notch 

Suprascapular notch 

Spine 



Greater tubercle 




Acromion 



Supraspinous 
fossa 



Infraspinous 
fossa 

Ivledial border 



Superior angle 




Coracold process 
Acromion 
Glenoid fossa 



, -^ Subscapular fossa 

IT 

Lateral border 



Fig.27.3 

Posteriorand anterior views of the left scapula 



Head 



Lesser 

tubercle 

Intertubercular 

sulcus 



Medial 

supracondylar 
ridge 

Ivledial 

epicondyle 




Anatomical 
neck 
Surgical 
neck 



Deltoid 
tuberosity 

Spiral 
groove 



Olecranon 
fossa 



Capitulum 

Trochlea 
Fig.27.4 

Anterior and posterior views of the left humerus 



The scapula (Fig. 27.3) 

• The scapula is triangular in shape. It provides an attachment for 
numerous muscles. 

• The glenoid fossa articulates with the humeral head (gleno-humeral 
joint), and the acromion process with the clavicle (acromioclavicular 
joint). 

The humerus (Fig. 27.4) 

• The humeral head consists of one third of a sphere. The rounded head 
articulates with the shallow glenoid. This arrangement permits a wide 
range of shoulder movement. 

• The anatomical neck separates the head from the greater and lesser 
tubercles. The surgical neck lies below the anatomical neck between 
the upper end of the humerus and shaft. The axillary nerve and cir- 
cumflex vessels wind around the surgical neck of the humerus. These 
are at risk of injury in shoulder dislocations and humeral neck fractures 
(see Fig. 34.3). 



• The greater and lesser tubercles provide attachment for the rotator 
c!(/f muscles. The tubercles are separated by the intertubercular sulcus 
in which the long head of biceps tendon courses. 

• A faint spiral groove is visible on the posterior aspect of the humeral 
shaft traversing obliquely downwards and laterally. The medial and lat- 
eral heads of triceps originate on either side of this groove. The radial 
nerve passes between the two heads. 

• The ulnar nerve winds forwards in a groove behind the medial 
epicondyle . 

• At the elbow joint: the trochlea articulates with the trochlear notch of 
the ulna; and the rounded capitulum with the radial head. The medial 
border of the trochlea projects inferiorly a little further than the lateral 
border. This accounts for the carrying angle, i.e. the slight lateral angle 
made between the arm and forearm when the elbow is extended. 



The osteology of the upper limb 63 



Olecranon 



Coronold 
process 



Radial 
tuberosity 



Attachment 
of 

pronator 
teres 

Interosseous 
borders 



Ulna styloid 
Fig.27.5 




Radial styloid 



Trochlear 
notch 

Head 

of 

radius 

Supinator 
crest 

Tuberosity 
of the 
ulna 



Dorsal 
tubercle 
Head 
of ulna 




The left radius and ulna in (a) supination and (b) pronation 



Fig.27.6 

X-ray of a fractureof the lower end 
of the radius (Colles' fracture) 



The radius and ulna (Fig. 27.5) 

• Both the radius and ulna have interosseous, anterior and posterior 
borders. 

• The biceps tendon inserts into the roughened posterior part of the 
radial tuberosity. The anterior part of the tuberosity is smooth where it 
is covered by a bursa. 

• The radial head is at its proximal end whilst the ulnar head is at its 
distal end. 

• The lower end of the radius articulates with the scaphoid and lunate 
carpal bones at the wrist joint. The distal ulna does not participate 
directly in the wrist joint. 

• The dorsal tubercle (of Lister) is located on the posterior surface of 
the distal radius. 



• In pronation/supination movements the radial head rotates in the 
radial notch of the ulna and the radial shaft pivots around the relatively 
fixed ulna (connected by the interosseous ligament). The distal radius 
rotates around the head of the ulna. 

A Colles fracture is a common injiuy occurring at the wrist in the 
elderly and usually osteoporotic population. It classically follows a fall 
on the outstretched hand. The fracture line is usually about 2.5 cm 
proximal to the wrist and the distal fragment displaces posteriorly (din- 
nerfork deformity when viewed from the side) and radially. Some 
degree of shortening often occurs due to impaction of the component 
parts (Fig.27.6). 



64 Upper limb 



Lunate — 
Triquetral 

Pisiform 

Hookof liamate 




Tubercle of scaplioid 
Trapezium 

Trapezoid 
Capitate 



Pisiform 

Triquetral 
Lunate 

Flexor retinaculum 
Scaphoid 

Fig.27.7 

The skeleton of the left hand, holding a cross-section through the carpal tunnel 



The hand (Fig. 27.7) 

The carpal bones are arranged into two rows. Tlie palmar aspect of the 
carpus is concave. This is brought about by the shapes of the con- 
stituent bones and the flexor retinaculum bridging the bones anteriorly 
to form the carpal tunnel (see Fig. 38.1). 

The scaphoid may be fractured through a fall on the outstretched 
hand. This injury is common in young adults and must be suspected 
clinically when tenderness is elicited by deep palpation in the anatomi- 



cal snuffbox. Radiographic changes are often not apparent and, if 
effective treatment is not implemented, permanent wrist weakness and 
secondary osteoarthritis may follow. The blood supply to the scaphoid 
enters via its proximal and distal ends. However, in as many as one 
third of cases the blood supply enters only from the distal end. Under 
these circumstances the proximal scaphoid fragment may be deprived 
of arterial supply and undergo avascular necrosis. 



The osteology of the upper limb 65 



28 Arteries of the upper limb 



Lateral thoracic 




Ulnar 
nerve 



artery 



Thoracoacromial 
artery 



Subscapular 

Axillary nerve 
Circumflex scapular 

Profunda brachii 
Median nerve 



Flexor retinaculum 



Ulnar artery 
Ulnar nerve - 
Pisiform 



Deep branch of ulnar 

Deep palmar arch 
Palmar metacarpal 



Superficial - 
palmar arch 




Radial artery 

Princeps 
pollicis 



Radialis 
indicis 



Common interosseous 
Posterior interosseous 

Radial nerve 
Radial artery 

Anterior interosseous 



Flexor carpi radialis 



Fig.26.1 

The arterial system of the upper limb. 
The main nerves that are related to 
the arteries are shown in green. 
Only the major arterial branches 
are labelled 



66 Upper limb 



The axillary artery 

• Course: the axillary artery commences at the lateral border of the 1 st 
rib as a continuation of the subclavian artery (see Fig. 60.1) and ends at 
the inferior border of teres major where it continues as the brachial 
artery. The axillary vein is a medial relation throughout its course. It is 
crossed anteriorly by pectoralis minor which subdivides it into three 
parts: 

• First part (medial to pectoralis minor). 

• Second part (behind pectoralis minor)— gives off the lateral 
thoracic artery (which helps to supply the breast) and the thora- 
coacromial artery (p. 75). 

• Third part (lateral to pectoralis minor) — gives off the subscapular 
artery which follows the lateral border of the scapula and gives off 
the circumflex scapular artery. 

The brachial artery 

• Course: the brachial artery commences at the inferior border of teres 
major as a continuation of the axillary artery and ends by bifurcating 
into the radial and ulnar arteries at the level of the neck of the radius. It 
lies immediately below the deep fascia throughout its course. The 
brachial artery is crossed superficially by the median nerve in the mid- 
arm from lateral to medial and hence lies between the median nerve 
(medial relation) and biceps tendon (lateral relation) in the cubital fossa 
(see Fig. 36.3). 

• Branches: 

• Profunda brachii— arises near the origin of the brachial artery and 
winds behind the humerus with the radial nerve in the spiral groove 
before taking part in the anastomosis around the elbow joint. 

• Other branches — include a nutrient artery to the humerus and 
superior and inferior ulnar collateral branches which ultimately 
take part in the anastomosis around the elbow. 

'Volkman's ischaemic contractiwe' is a deformity arising as a result 
of brachial artery spasm following injury (usually from fractures of the 
distal humerus). The reduced arterial flow results in ischaemic necro- 
sis of the forearm musculature which is eventually replaced by short- 
ened fibrous tissue. In the classical deformity the forearm is wasted and 
the wrist joint flexed with the fingers extended. When the wrist is 
extended the fingers flex. 

The radial artery 

• Course: the radial artery arises at the level of the neck of the radius 
from the bifurcation of the brachial artery. It passes over the biceps ten- 
don to lie firstly on supinator then descends on the radial side of the 
forearm, lying under the edge of brachioradialis in the upper half of 
its course and then between the tendons of brachioradialis and flexor 
carpi radialis in the lower forearm. The radial artery passes sequentially 
over supinator, pronator teres, the radial head of flexor digitorum 
superflcialis, flexor pollicis longus and pronator quadratus. At the wrist 



the artery lies on the distal radius lateral to the tendon of flexor carpi 
radialis. This is where the radial pulse is best felt. 

• Branches: 

• Palmar and dorsal carpal branches are given off at the wrist. 

• A superficial paltnar branch arises at the wrist which supplies the 
thenar muscles and consequently anastomoses with the superficial 
palmar branch of the ulnar artery to form the supeificial palmar 
arch. 

• The radial artery passes backwards under the tendons of abductor 
pollicis longus and extensor pollicis brevis to enter the anatomical 
snuffbox. It consequently passes over the scaphoid and trapezium 
in the snuffbox and exits by passing between the two heads of 
adductor pollicis to enter the palm and forms the deep palmar arch 
with a contribution from the ulnar artery {deep palmar branch). It 
gives off Ihe princeps pollicis to the thumb and the radialis indicis 
to the index finger. 

• The deep palmar arch gives off three palmar metacarpal arteries 
which subsequently join the common palmar digital arteries (from 
the superficial arch) to supply the digits. 

The ulnar artery 

• Course: the ulnar artery commences as the terminal bifurcation of 
the brachial artery at the level of the neck of the radius. It passes deep to 
the deep head of pronator teres and deep to the fibrous arch of flexor 
digitorum superflcialis and descends on flexor digitorum profundus 
with the ulnar nerve lying medial to it and flexor carpi ulnaris overlap- 
ping it in the proximal half of the forearm. 

At the wrist both the ulnar artery and nerve lie lateral (radial) to 
flexor carpi ulnaris and pass over the flexor retinaculum giving carpal 
branches which contribute to the dorsal andpalmar carpal arches. 

• Branches: 

• A deep palmar branch completes the deep palmar arch (see above) 
and the ulnar artery continues as the superficial palmar arch which 
is completed by the superflcial palmar branch of the radial artery. 

• The common interosseous artery (see below). 

The common interosseous artery 

The common interosseous artery is the flrst ulnar branch to arise and it 
subdivides into the: 

• Anterior interosseous artery: descends with the interosseous branch 
of the median nerve on the anterior surface of the interosseous 
membrane. It predominantly supplies the flexor compartment of the 
forearm. 

• Posterior interosseous artery: passes above the upper border of the 
interosseous membrane to enter the extensor compartment where it 
runs with the deep branch of the radial nerve supplying the extensor 
muscles of the forearm, eventually anastomosing with the anterior 
interosseous artery. 



Arteries of the upper limb 67 



29 The venous and lymphatic drainage of the upper limb and the breast 



Fig. 29.1 

The superficial venous 
system of the upper 
limb and two major 
cutaneous nerves 



Medial cutaneous nerve 
of forearm 

Brachial artery 
Median nerve 




Cephalic vein pierces 
clavipectoral fascia 



Deltoid 
Pectoralis major 

Cephalic vein 

Median 
cubital vein 

Tendon 
of biceps 

Lateral 
cutaneous 
nerve of 
forearm 



Bicipital aponeurosis 



Basilic vein 




Suspensory ligament 

Alveoli of breast 

Lactiferous duct 

Lactiferous 
sinus 




Pectoralis 
minor 

Pectoralis 
major 

Intercostals 



Nipple 
Areola 

Montgomery's 
gland 

Fat 

Fig. 29.3 

A section through the breast to show its major relations. 
The inset shows the radial arrangement of the 
lactiferous ducts 



Right lymph duct 




Lateral group 
Central group 



Axillary vessels 



Supratrochlear group 



Fig. 29.2 

The lymph nodes of the axilla and the lymphatic drainage of the breast 



Inferior deep cervical 
(supraclavicular) group 

Delto-pectoral group 
Apical group 

Posterior group 

Anterior (pectoral) group 

Parasternal group 
(inside chest) 



68 Upper limb 



Venous drainage of the upper limb (Fig. 29. i) 

As in tlie lower limb the venous drainage comprises interconnected 
superficial and deep systems. 

• The superficial system: comprises the cephalic and basilic veins. 

• The cephalic vein commences from the lateral end of the dorsal 
venous network overlying the anatomical snuffbox. It ascends the 
lateral, then anterolateral, aspects of the forearm and arm and 
finally courses in the deltopectoral groove to pierce the clavipec- 
toral fascia and drain into the axillary vein. 

• The basilic vein commences from the medial end of the dorsal 
venous network. It ascends along the medial then anteromedial 
aspects of the forearm and arm to pierce the deep fascia (in the 
region of the mid-arm) to join with the venae comitantes of the 
brachial artery to form the axillary vein. 

The two superficial veins are usually connected by a median cubital 
vein in the cubital fossa. 

• The deep veins: consist of venae comitantes (veins which accom- 
pany arteries). 

The superficial veins of the upper limb are of extreme clinical import- 
ance for phlebotomy and peripheral venous access. The most com- 
monly used sites are the median cubital vein in the antecubital fossa and 
the cephalic vein in the forearm. 

Lymptiatic drainage of ttie ctiestwall and 
upper limb (Fig. 29.2) 

Lymph from the chest wall and upper limb drains centrally via axillary, 
supratrochlear and infraclavicular lymph nodes. 

Axillary lymph node groups 

There are approximately 30-50 lymph nodes in the axilla. They are 
arranged into five groups: 

• Anterior (pectoral) group: these lie along the anterior part of the 
medial wall of the axilla. They receive lymph from the upper anterior 
part of the trunk wall and breast. 

• Posterior (subscapular) group: these lie along the posterior part of 
the medial wall of the axilla. They receive lymph from the upper pos- 
terior trunk wall down as far as the iliac crest. 

• Lateral group: these lie immediately medial to the axillary vein. 
They receive lymph from the upper limb and the breast. 

• Central group: these lie within the fat of the axilla. They receive 
lymph from all of the groups named above. 

• Apical group: these lie in the apex of the axilla. They receive lymph 
from all of the groups mentioned above. From here lymph is passed to 
the thoracic duct (on the left) or right lymphatic trunks (see Fig. 3.3), 
with some passing to the itrferior deep cervical (supraclavicular) 
group. 

Lymph node groups in the arm 

• The supratrochlear group of nodes lie subcutaneously above the 



medial epicondyle. They drain lymph from the ulnar side of the forearm 
and hand. Lymph from this group passes to the lateral group of axillary 
lymph nodes and thence drains centrally. 

• A small amount of lymph from the radial side of the upper limb 
drains directly into the infraclavicular group of nodes. This group is 
arranged around the cephalic vein in the deltopectoral groove. From 
this point the efferent vessels pass through the clavipectoral fascia to 
drain into the apical group of axillary nodes and thence centrally. 

This itrformatiotr can be applied to the clinical scenario. If a patient 
presents with an infected insect bite of the thumb, the infraclavicular 
nodes would reactively enlarge. If, however, infection occurred on the 
patient's little finger, lymphadenopathy of the supratrochlear nodes 
would result. 

The breast (Fig. 29.3) 

The breasts are present in both sexes and have similar characteristics 
until puberty when, in the female, they enlarge and develop the capac- 
ity for milk production. The breasts are essentially specialized skin 
glands comprising fat, glandular and connective tissue. The base of the 
breast lies in a constant position on the anterior chest wall. It extends 
from the 2nd to 6th ribs anteriorly and from the lateral edge of the ster- 
num to the mid-axillary line laterally. A part of the breast, the axillary 
tail, extends laterally through the deep fascia beneath pectoralis to enter 
the axilla. Each breast comprises 15-30 functional ducto-lobular units 
arranged radially around the nipple. The lobes are separated by fibrous 
septa (suspensory ligaments) which pass from the deep fascia to the 
overlying skin thereby giving the breast structure. A lactiferous duct 
arises from each lobe and converges on the nipple. In its terminal por- 
tion the duct is dilated (lactiferous sinus) and thence continues to the 
nipple from where milk can be expressed. The areola is the darkened 
skin that surrounds the nipple. Its surface is usually irregular due to 
multiple small iuh&Lcle.^— Montgomery' s glands. 

• Blood supply: is from the perforating branches of the internal 
thoracic artery (p. 13) and the lateral thoracic and thoracoacromial 
branches of the axillary artery (p. 67). The venous drainage corres- 
ponds to the arterial supply. 

• Lymphatic drainage: from the lateral half of the breast is to the 
anterior axillary nodes. Lymph from the medial breast drains into the 
internal mammary nodes (adjacent to the internal thoracic vessels 
beneath the chest wall). 

Lymph drainage in carcinoma of the breast 

The axillary lymph nodes represent an early site of metastasis from prim- 
ary breast malignancies and their surgical removal and subsequent 
examination provide important prognostic information as well as a 
basis for choice of adjuvant treatment. Damage to axillary lymphatics 
during surgical clearance of axillary nodes or resulting from radio- 
therapy to the axilla increases the likelihood of subsequent upper limb 
lymphoedema. 



The venous and lymphatic drainage of the upper limb and the breast 69 



30 Nerves of the upper limb I 



Fig. 30.1 

The brachial plexus. 
Lateral cord, red; 
medial cord, yellow; 
posterior cord, green 



Trunks 



Lateral pectoral nerve — 
(pectoralis major 
pectoralis minor) 

Musculocutaneous nerve 

Median nerve 

Radial nerve 



Axillary nerve 

Fig.30.2 

The course and main 
branches of the 
radial nerve 



Pierces lateral 
intermuscular 
septum 



Superficial 



radial nerve 

(supplies 
dorsum of ha 
and late 
31/2 digits 





Radial nerve 

Profunda brachii artery 

Branches to triceps 

Posterior cutaneous nerve 
of forearm (supplies the 
posterior skin of forearm) 

Branches to brachialis and 
brachioradialis plus extensor 
carpi radialis longus 

Posterior interosseous nerve 

pierces supinator and supplies it. 
Also supplies: 

Extensor carpi radialis longus and brevis 
Extensors digitorum, digiti minimi, 
carpi ulnaris 
Abductor pollicis longus 
Extensor pollicis brevis and longus 
Extensor indicis 



Recurrent branch to; 



abductor pollicis brevis, 
flexor pollicis brevis, 
opponens pollicis 

Fig.30.3 

The course and main 
branches of the median nerve 



Dorsal scapular nerve 
(Rhomboids, levator scapulae) 

Suprascapular nerve 
(supraspinatus, infraspinatus) 



Long thoracic nerve 
(serratus anterior) 



Subscapular nerves 
(subscapularis, teres major) 

Medial pectoral nerve 

(pectoralis major, pectoralis minor) 

Thoracodorsal nerve 
(latissimusdorsi) 

Medial cutaneous nerve of arm 
Medial cutaneous nerve of forearm 
Ulnar nerve 



Lateral and medial roots 
Brachial artery 
Median nerve 



Pronator teres 

Ulnar artery 

Deep head of pronator teres 

Anterior interosseous branch 

to flexor pollicis longus, 
V2flexordigitorum profundus 
and pronator c|_uadratus 

Branches to flexor carpi radialis 
flexor digitorum superficialis, 
palmaris longus 

Flexor retinaculum 

Palmar cutaneous branch 

To lateral two (1st and 2nd) 
lumbricals 

Cutaneous branches to the 
palmar skin of lateral 3V2 digits 




70 Upper limb 



The brachial plexus (C5,6,7,8,T1) (Fig. 30.i) 

• The plexus arises as five roots. Thiese are tiie anterior primary rami of 
C5,6,7,8,T1. Tlie roots lie between scalenus anterior and scalenus 
medius. 

• The three trunks (upper, middle and lower) lie in the posterior tri- 
angle of the neck. They pass over the 1 st rib to lie behind the clavicle. 

• The divisions form behind the middle third of the clavicle around the 
axillary artery. 

• The cords lie in the axilla and are related medially, laterally and pos- 
teriorly to the second part of the axillary artery. 

• Terminal nerves arise from the cords surrounding the third part of the 
axillary artery. 

The axillary nerve (C5,6) 

• Type: mixed sensory and motor nerve. 

• Origin: it arises from the posterior cord of the brachial plexus. 

• Course: it passes through the quadrangular space with the posterior 
circumflex humeral artery. It provides: a motor supply to deltoid and 
teres minor; a sensory supply to the skin overlying deltoid; and an articu- 
lar branch to the shoulder joint. 

• Effect of injury: the axillary nerve is particularly prone to injury 
from the downward displacement of the humeral head during shoulder 
dislocations. 

• Motor deficit— loss of deltoid abduction with rapid wasting of this 
muscle. Loss of teres minor function is not detectable clinically. 

• Sensory deficit— is limited to the 'badge' region overlying the 
lower half of deltoid. 

The radial nerve (C5,6,7,8,T1) (Fig. 30.2) 

• Type: mixed sensory and motor. 

• Origin : it arises as a continuation of the posterior cord of the brachial 
plexus. 

• Course and branches: it runs with the profunda brachii artery 
between the long and medial heads of triceps into the posterior com- 
partment and down between the medial and lateral heads of triceps. 
At the midpoint of the arm it enters the anterior compartment by piercing 
the lateral intermuscular septum. In the region of the lateral epicondyle 
the radial nerve lies under the cover of brachioradialis and divides 
into the superficial radial and posterior interosseous nerves. 

The branches of the radial nerve include: branches to triceps, bra- 
chioradialis and brachialis as well as some cutaneous branches. It ter- 
minates by dividing into two major nerves: 

• The posterior interosseous nerve — passes between the two heads 
of supinator at a point three fingerbreadths distal to the radial 
head thus passing into the posterior compartment. It supplies the 
extensor muscles of the forearm. 

• The superficial radial ;;e/-ve— descends the forearm under the cover 
of brachioradialis with the radial artery on its medial side. It termin- 



ates as cutaneous branches supplying the skin of the back of the 
wrist and hand. 

• Effect of injury (Fig. 31.2): e.g. humeral shaft fracture resulting in 
damage to the radial nerve in the spiral groove. 

• Motor deficit— loss of all forearm extensors: wristdrop. 

• Sensory deficit— usually small due to overlap: sensory loss over the 
anatomical snuffbox is usually constant. 

The musculocutaneous nerve (C5,6,7) 

• Type: mixed sensory and motor. 

• Origin : it arises from the lateral cord of the brachial plexus. 

• Course: it passes laterally through the two conjoined heads of cora- 
cobrachialis and then descends the arm between brachialis and biceps, 
supplying all three of these muscles en route. It pierces the deep fascia 
just below the elbow (and becomes the lateral cutaneous nerve of the 
forearm). Here it supplies the skin of the lateral forearm as far as the 
wrist. 

The median nerve (C6,7,8,T1) (Fig. 30.3) 

• Type: mixed sensory and motor. 

• Origin: it arises from the confluence of two roots from the medial 
and lateral cords lateral to the axillary artery in the axilla. 

• Course and branches: the median nerve initially lies lateral to the 
brachial artery but crosses it medially in the mid-arm. In the cubital 
fossa it lies medial to the brachial artery which lies medial to the bicipi- 
tal tendon. The median nerve passes deep to the bicipital aponeurosis 
then between the two heads of pronator teres. A short distance below 
this the anterior interosseous branch is given off. This branch descends 
with the anterior interosseous artery to supply the deep muscles of the 
flexor compartment of the forearm except for the ulnar half of flexor 
digitorum profundus. In the forearm the median nerve lies between 
flexor digitorum superficialis and flexor digitorum profundus and 
supplies the remaining flexors except for flexor carpi ulnaris. A short 
distance above the wrist it emerges from the lateral side of flexor 
digitorum superficialis and gives off the palmar cutaneous branch 
which provides a sensory supply to the skin overlying the thenar 
eminence. 

At the wrist the median nerve passes beneath the flexor retinaculum 
(i.e. through the carpal tunnel) in the midline and divides here into its 
terminal branches: the recurrent branch to the muscles of the thenar 
eminence (but not adductor pollicis); the branches to the 1st and 2nd 
lumbricals; and the cutaneous supply to the palmar skin of the thumb, 
index, middle and lateral half of the ring fingers. 

• Effect of injury (see Fig. 31.2): e.g. compression as in carpal tunnel 
syndrome. 

• Motor (fe/7c/r— weakness and wasting of the thenar muscles. 

• Sensory deficit — involves the skin over the lateral palm and lateral 
three digits. This is highly variable due to overlap. 



Nerves of the upper limb I 71 



31 Nerves of the upper limb II 



Fig.31.1 

The course and main 
branches of the ulnar nerve 



Adductor pollicis 



Deep branch to; 

Flexordigiti minimi 
Abductor digiti minimi 
Opponens digit minimi 
Ivied iai two lumbricals 
All the interossei 
Adductor pollicis 




Brachial artery 

Ulnar nerve 

Pierces medial 
intermuscular septum 



Flexor carpi ulnaris 



Dorsal cutaneous branch 

(backs of medial lV2digits) 



Ulnar artery 
Flexor retinculum 

Superficial branch 

(palmar IV2 digits) 




(a) 

Radial nerve palsy 



Wasting of 
thumb muscles 




(b) 

Median nerve palsy 




(c) 

Ulnar nerve palsy 



Fig.31.2 

Some common nerve palsies and the associated areas of altered sensation. 
These are very variable 



72 Upper limb 



The ulnar nerve (C8,T1) (Fig. 3i.i) 

• Type: mixed sensory and motor. 

• Origin : from tlie medial cord of the bracliial plexus. 

• Course and branches: it runs on coracobracliialis to tlie mid-arm 
wliere it pierces thie medial intermuscular septum with the superior 
ulnar collateral artery to enter the posterior compartment. It winds 
under the medial epicondyle and passes between the two heads of 
flexor carpi ulnaris to enter the forearm and supplies flexor cari ulnaris 
and half of flexor digitorum profundus. In the lower forearm the artery 
lies lateral to the ulnar nerve and the tendon of flexor carpi ulnaris. Here 
dorsal and palmar cutaneous branches are given off. The ulnar nerve 
passes superficial to the flexor retinaculum and subsequently divides 
into terminal branches. These are: 

• The superficial terminal fora«c/!— terminates as terminal digital 
nerves supplying the skin of the little and medial half of the ring 
fingers. 

• The deep terminal branch— supplies the hypothenar muscles as 
well as two lumbricals, the interossei and adductor pollicis. 

• Effect of injury (Fig. 31.2): occurs commonly at the elbow (e.g. 
fracture of the medial epicondyle) or at the wrist due to a laceration. 

• Motor iie/7CiY— with low lesions the hand becomes 'clawed'. Owing 
to the loss of interossei and lumbrical function the metacarpopha- 
langeal joints of the ring and little fingers hyperextend and their 
interphalangeal joints flex. The 'clawing' is attributed to the un- 
opposed action of the extensors and flexor digitorum profundus. 
When injury occurs at the elbow or above, the ring and little fingers 
are straighter because the ulnar supply to flexor digitorum profun- 
dus is lost. The small muscles of the hand waste with the exception 
of the thenar and lateral two lumbrical muscles (supplied by the 
median nerve). 

• Sensory deficit— occurs to the palmar and dorsal surfaces of the 
hand and medial 11/2 digits. The loss is highly variable due to 
overlap. 



Other branches of the brachial plexus 

Supraclavicular branches 

• Suprascapular nerve (C5,6): passes through the suprascapular 
notch to supply supra- and infraspinatus muscles. 

• Long thoracic nerve (of Bell) (C5,6,7): supplies serratus anterior. 

Infraclavicular branches 

• Medial and lateral pectoral nerves: supply pectoralis major and 
minor. 

• Medial cutaneous nerves of the arm and forearm. 

• Thoracodorsal nerve (C6,7,8): supplies latissimus dorsi. 

• Upper and lower subscapular nerves: supply subscapularis and 
teres major. 

Brachial plexus injuries 

Erb-Duchenne paralysis 

Excessive downward traction on the upper limb during birth can result 
in injury to the C5 and C6 roots. This results in paralysis of the deltoid, 
the short muscles of the shoulder, brachialis and biceps. The combined 
effect is that the arm hangs down by the side with the forearm pronated 
and the palm facing backwards. This has been termed the 'waiter' s tip' 
position. 

Klumpke's paralysis 

Excessive upward traction on the upper limb can result in injury to the 
Tl root. As the latter is the nerve supply to the intrinsic muscles of the 
hand this injury residts in 'clawing' (extension of the metacarpopha- 
langeal joints and flexion of the interphalangeal joints) due to the 
imopposed action of the longflexors and extensors of the fingers. There 
is often an associated Horner' s syndrome (ptosis, pupillary constric- 
tion and ipsilateral anhidrosis) as the traction injury often involves the 
cervical sympathetic chain. 



Nerves of the upper limb 11 13 



32 The pectoral and scapular regions 



Costoclavicular Clavicle 

ligament Intra-articular 




First costal 
cartilage 



Fig. 32.1 

The sterno-clavicularjoint 



Manubrium 

sterni Thoracoacromial 

artery 

Lateral pectoral 

nerve 

Coraco-brachialis 



Trapezius — 

Infraspinatu 
and teres 
minor 



Pectoralis minor 

Biceps 

Brachialis 



Sternocleidomastoid 

Pectoralis major (clavicular head) 

Deltopectoral triangle 

Trapezius 

Deltoid 
Cephalic vein 
Pectoralis major 
(sternocostal 
head) 

Coraco- 
brachialis 
Biceps 
Triceps 
(medial head) 
Serratus 
anterior 
Brachialis 
Biceps tendon 





Fig. 32.2 

Muscles of the pectoral region and upper arm 



Levator scapulae 



Brachioradialis 
Bicipital aponeurosis 



Supraspinatus 



Supraspinatus 
Infraspinatus 

Teres minor 
Teres major 



Suprascapular artery 

Infraspinatus 
Teres minor 

Axillary nerve 
and posterior 
circumflex 
humeral artery 

Triceps 




Fig. 32.3 

Musclesof the scapular region and back 



Circumflex 
scapular artery 

Fig. 32.4 

The triangular and quadrangular spaces 



74 Upper limb 



The upper limb is attached to the axial skeleton by way of the scapula 
and clavicle. It should be noted that this involves only two small 
joints — the acromioclavicular and sternoclavicular joints. The main 
attachment between the upper limb and the axial skeleton is muscular. 

The muscles of the outer chest wall (Figs 32.2 and 32.3) 

See Muscle index, p. 162. 

• Muscles of the outer anterior chest wall include pectoral is major and 
pectoralis minor. 

• Muscles of the back and shoulder include: latissimus dorsi, trapez- 
ius, deltoid, levator scapulae, serratus anterior, teres major and minor, 
rhomboids major and minor, subscapularis, supraspinatus and 
infraspinatus. 

The sternoclavicular joint (Fig. 32. i) 

• Type: atypical synovial joint. 

• The articulation is between the sternal end of the clavicle and the 
manubrium. The articular surfaces are covered with fibrocartilage as 
opposed to the usual hyaline. 

• A fibrocartilaginous articular disc separates the joint into two 
cavities. 

• The fulcrum of movement at this joint is the costoclavicular liga- 
ment, i.e. when the lateral end of the clavicle moves upwards the medial 
end moves downwards. 

The acromioclavicular joint 

• Type: atypical synovial joint. 

• The articulation is between the lateral end of the clavicle and the 
medial border of the acromion. As for the sternoclavicular joint, the 
articular surfaces are covered with fibrocartilage and an articular disc 
hangs into the joint from above. 



• This is a weak joint. The main bond between the clavicle and the 
scapula is the coracoclavicular ligament (see Fig. 34.1). 

The deltopectoral triangle, clavipectoral fascia and the 
anatomical spaces (Fig. 32.2) 

• The deltopectoral triangle is the region that is bounded by deltoid, 
pectoralis major and superiorly by the small bare length of clavicle that 
does not provide an origin for either of these muscles. 

• The clavipectoral fascia is a sheet of strong connective tissue. The 
uppermost part of this fascia forms the floor of the deltopectoral tri- 
angle. It is attached superiorly to the clavicle around the subclavius 
muscle. Below it splits to enclose pectoralis minor. The fascia con- 
tinues downwards as the suspensory ligament of the axilla and becomes 
continuous with the fascial floor of the armpit. The clavipectoral fascia 
is pierced by four structures in total. Two structures drain inwards: (1) 
the cephalic vein and (2) lymphatics from the infraclavicular nodes. 
Similarly, two structures pierce the fascia to pass outwards: (3) the tho- 
racoacromial artery and (4) the lateral pectoral nerve (which supplies 
pectoralis major and minor). 

• Two important anatomical spaces are found in the shoulder region 
(Fig. 32.4): 

• The quadrangular space is an intermuscular space through which 
the axillary nerve and posterior circumflex humeral vessels pass 
through backwards to encircle the surgical neck of the humerus. It 
is bounded above by subscapularis and teres minor and below by 
teres major. The long head of triceps and the surgical neck of the 
humerus are medial and lateral boundaries, respectively. 

• The triangular space is bounded by teres major, teres minor and 
the long head of triceps. The circumflex scapular artery passes 
from front to back through this space to gain access to the 
infraspinous fossa. 



The pectoral and scapular regions 75 



33 The axilla 



Trapezius 



Clavicle 



Subclavius 

Clavipectoral 

fascia 



Axillary space 

Pectoralis 
minor 

Pectoralis 
major 

Fascial floor 
of axilla 




Short head of biceps 
Coracobrachialis 



Long head 
of biceps 
(tendon) 



Pectoralis minor 

Pectoralis major 




Lateral cord 
Axillary artery 
Medial cord 
Axillary vein 
Posterior cord 
Latissimus 
dorsi (tendon) 
Chest wall 



Fig.33.1 

Vertical and horizontal sections through the axilla; the planes of the sections are shown in the central diagram 



Serratus anterior 
Subscapularis 



Cephalic vein 



Lateral cord 



Lateral pectoral 



Musculocutaneous 




Median 



Fig.33.2 

The main contents of the axilla from the front. 

The posterior cord is hidden behind the axillary artery 



Axillary artery 
Axillary vein 
Medial pectoral 

Medial cord 

Lateral thoracic artery 
Medial cutaneous 
of arm 

Pectoralis minor 



Medial cutaneous 
of forearm 

Ulnar 
Radial 



76 Upper limb 



The major nerves and vessels supplying and draining the upper limb 
pass through the axilla. 

The axilla is a three-sided pyramid. Its apex is the small region 
between the 1st rib, the clavicle and the scapula through which the 
major nerves and vessels pass. 

The walls of the axilla are composed as follows: 

• The anterior wall is made up from the pectoralis major and minor 
muscles and the clavipectoral fascia. 

• The posterior wall is made up of the subscapularis, teres major and 
latissimus dorsi. 

• The medial wall consists of the upper part of serratus anterior, the 
upper ribs and intercostals. 

• The lateral wall is almost non-existent but can be seen as the latis- 
simus dorsi as it inserts into the floor of the intertubercular (bicipital) 
sulcus. Running downwards from above are the corachobrachialis and 
short head of biceps as well as the long head of biceps in the intertuber- 
cular sulcus. 

The contents of the axilla (Figs 33.1 and 33.2) 

• The axillary artery: an important anastomosis exists between the 
subclavian artery and third part of the axillary artery — the scapular 



anastomosis. It compensates for compromised flow that may occur due 
to axillary artery obstruction. The principal arteries involved are the 
suprascapular, from the third part of the subclavian artery, and the sub- 
scapular, from the third part of the axillary artery with contributions 
from other arteries. 

• The axillary vein: is formed by the confluence of the venae comit- 
antes of the axillary artery and the basilic vein (p. 69). It becomes the 
subclavian vein at the lateral border of the 1st rib. The named tributar- 
ies of the axillary vein correspond to those of the axillary artery. 

• The cords and branches of the brachial plexus: see p. 7 1 . 

• The axillary lymph nodes: see p. 69. 

• Fat. 

Axillary clearance 

In breast cancer surgery the axillary lymph nodes are cleared rou- 
tinely. During the dissection for this procedure one must clearly iden- 
tify the axillary vein, and the thoracodorsal (C6,7,8) and long thoracic 
(C5,6,7) nerves. Injury to the thoracodorsal nerve results in paralysis 
of latissimus dorsi. Injiuy to the long thoracic nen'e causes paralysis of 
serratus anterior resulting in weakened arm abduction. On clinical 
examination the latter injury results in winging of the scapula. 



The axilla 11 



34 The shoulder (gleno-humeral) joint 



Coracoclavicular , Coraco-acromial 
ligament / ligament 




Long head 
of bleeps 



Subscapularis 

Subscapular 
bursa 

Glenoid fossa 



Capsular ligament 



Fig. 34.1 

The glenoid cavity and its associated 
ligaments and rotator cuff muscles 



Subacromial bursa 

Acromion 
Supraspinatus 



Infraspinatus 
Teres minor 

Long head 
of triceps 



Supraspinatus 
(seen through 



suprasca 



Coraco-acromial 
ligament 




Tendon of supraspinatus, 

blending with capsular 

ligament 

Coracohumeral ligament 

Opening of subscapularis 

bursa 

Subscapularis 

Sheath of synovial 
membrane 

Long head of biceps 



Long head 
of triceps 



Fig. 34.2 

Anterior aspect of the shoulder joint 




Fig. 34.3 

X-ray of a dislocated shoulder 



78 Upper limb 



See Figs 34. land 34.2. 

• Type: the shoulder is a synovial 'ball and socket' joint which permits 
multiaxial movement. It is formed by the articulation of the humeral 
head with the shallow glenoid fossa of the scapula (see p. 63). The 
glenoid is slightly deepened by a fibrocartilaginous rim — the glenoid 
labriim. Both articular surfaces are covered with hyaline cartilage. 

• The capsule: of the shoulder joint is lax permitting a wide range of 
movement. It is attached medially to the margins of the glenoid and lat- 
erally to the anatomical neck of the humerus except inferiorly where it 
extends to the surgical neck. The capsule is significantly strengthened 
by slips from the surrounding rotator cuff muscle tendons. 

• Stability: is afforded by the rotator cuff and the ligaments around the 
shoulder joint. The latter comprise: three gleno-hiimeral ligaments 
which are weak reinforcements of the capsule anteriorly; a coraco- 
humeral ligament which reinforces the capsule superiorly; and a cora- 
coacromial ligament which protects the joint superiorly. The main 
stability of the shoulder is afforded by the rotator cuff. The cuff com- 
prises; siibscapiilaris, siipraspinatus, infraspinatus and teres minor 
(see Muscle index, p. 162) which pass in front of, above and behind the 
joint, respectively. Each of these muscles can perform its own function 
and when all are relaxed free movement is possible, but when all are 
contracted they massively reinforce shoulder stability. 

• Bursae: two large bursae are associated with the shoulder joint. The 
subscapular bursa separates the shoulder capsule from the tendon of 
subscapularis which passes directly anterior to it. The subscapular 
bursa communicates with the shoulder joint. The subacromial bursa 
separates the shoulder capsule from the coracoacromial ligament 
above. The subacromial bursa does not communicate with the joint. 
The tendon of supraspinatus lies in the floor of the bursa. Inflammation 
of the bursa due to adjacent inflammation of the supraspinatus tendon 
caused by impingement of the supraspinatus tendon on the coracoacro- 
mial ligament gives rise to severe pain and limitation of shoulder 
abduction (classically between 60 and 120°) known as the painful arc 
syndrome. 

• The synovial membrane: lines the capsule and covers the articular 
surfaces. It surrounds the intracapsular tendon of biceps and extends 
slightly beyond the transverse humeral ligament as a sheath. It forms 
the subscapular bursa anteriorly by protruding through the anterior wall 
of the capsule. 



• Nerve supply: from the axillary (C5,6) and suprascapular nerves 
(C5,6). 

Shoulder movements 

The shoulder is a 'ball and socket' joint allowing a wide range of move- 
ment. Much of this range is attributed to the articulation of the shallow 
glenoid with a rounded humeral head. The drawback, however, is that 
of compromised stability of the joint. 

The principal muscles acting on the shoulder joint are; 

• Flexion (0-90°): pectoralis major, coracobrachialis and deltoid 
(anterior fibres). 

• Extension (0-45°): teres major, latissimus dorsi and deltoid (poster- 
ior fibres). 

• Internal (medial) rotators (0-40°): pectoralis major, latissimus 
dorsi, teres major, deltoid (anterior fibres) and subscapularis. 

• External (lateral) rotators (0-55°): infraspinatus, teres minor and 
deltoid (posterior fibres). 

• Adductors (0-45°): pectoralis major and latissimus dorsi. 

• Abductors (0-180°): supraspinatus, deltoid, trapezius and serratus 
anterior. 

Abduction at the shoulder joint is initiated by supraspinatus; deltoid 
continues it as soon as it obtains sufficient leverage. Almost simultan- 
eously the scapula is rotated so that the glenoid faces upwards; this 
action is produced by the lower fibres of serratus anterior which are 
inserted into the inferior angle of the scapula and by the trapezius which 
pulls the lateral end of the spine of the scapula upwards and the medial 
end downwards. 

Shoulder dislocation (Fig. 34.3) 

As has been described above, stability of the shoulder joint is mostly 
afforded anteriorly, superiorly and posteriorly by the rotator cuff. 
Inferiorly, however, the shoulder is unsupported and strong abduction, 
coupled with external rotation, can force the head of the humerus 
downwards and forwards (sometimes damaging the axillary nerve) to 
the point that the joint dislocates. This is termed the anterior shoidder 
dislocation as the head usually comes to lie anteriorly in the siibcora- 
coid position. Sometimes the force of the injury is sufficient to tear the 
glenoid labrum anteriorly thereby facilitating recurrence. A surgical pro- 
cedure is always required when the latter has led to repeated dislocations. 



The shoulder (gleno-humeral) joint 79 



35 The arm 



Deltoid 



Biceps 
retracted 




Bracliioradialis 

Tendon of 
biceps 

Lateral 
cutaneous 
nerve of 
forearm 

Fig.35.1 

The main blood vessels and nerves 
of the front of the arm 



-Pectoralis 
major 



Brachial artery 
on brachialis 



Median nerve 



Bicipital 
aponeurosis 



Cephalic vein 
Brachioradialis 
Radial nerve 



Extensor carpi 
radialis longus 

Lateral 

intermuscular 
septum 




Supinator 



Supraspinatus 
Suprascapular nerve 

Infraspinatus 

Teres minor 

Axillary nerve 



Deltoid 
(pulled back) 

Lateral head of 
triceps 

Radial nerve 

Medial head of 
triceps 



Deep branch 
Superficial branch 




Fig. 35.3 

Cross-section through the arm just above the elbow. 

The thick black lines represent the deep fascia and the intermuscular septa 



Fig.35.2 

The major nerves in the back of the arm 

Biceps brachii 
Loose connective tissue 
Median nerve 
Brachial artery 

Basilic vein 

Brachialis 

Medial intermuscular septum 

Ulnar nerve 

Humerus 

Triceps 

Deep fascia 

Fat of superficial fascia 

Skin 



80 Upper limb 



When viewed in cross-section thie arm consists of skin and subcutan- 
eous tissue in whicli the superficial veins and sensory nerves course. 
Below lies a deep fascial layer. Medial and lateral intermuscular septa 
arise from the supracondylar lines of the humerus and extend to the 
deep fascia thereby dividing the arm into anterior and posterior 
compartments. 

The anterior (flexor) compartment contents include (Figs 35.1 
and 35.3): 

• The flexor muscles: coracobrachialis, biceps and brachialis (see 
Muscle index, p. 162). 

• The brachial artery and branches: see p. 67. 

• The median nerve: see p. 7 1 . 

• The ulnar nerve (in the upper arm only— as it pierces the medial inter- 
muscular septum to pass into the posterior compartment in the mid- 
arm): seep. 73. 



• The musculocutaneous nerve and branches (remember that, after pro- 
viding muscular supply to the flexor compartment, this nerve pierces 
the deep fascia in the mid-arm to become the lateral cutaneous nerve of 
the forearm): see p. 71 . 

• The basilic vein (in the upper arm only — in the lower arm it is sub- 
cutaneous): see p. 69. 

The posterior (extensor) compartment contents include 
(Figs 35.2 and 35.3): 

• The extensor muscles: triceps (see Muscle index, p. 162). 

• The radial nerve and branches: see p. 71 . 

• The profunda brachii artery: see p. 67. 

• The ulnar nerve (in the lower arm only): see p. 73. 



The arm 8 1 



36 The elbow joint and cubital fossa 



Corono\d 
fossa 

Trochlea 

Coronoid 
process of ulna 




Attachment of 
capsular ligament 

Radial fossa 



Capitulum 
Head of radius 

Radial tuberosity 



Fig.36.1 

The bones of the elbow joint; 
the dotted lines represent the 
attachmentsof the capsular ligament 



Biceps 

EJrachialis 

Biceps tendon 
Brachioradialis 



Pronator 
teres 



Triceps 
tendon 

Medial 
ligament 



Annular 
ligament IV 

L ~ 



Ulna 




Fig.36.3 

The cubital fossa. It is crossed by the median cubital vein 



Median nerve 
EJrachial artery 
Medial epicondyle 

Bicipital aponeurosis 



Flexor carpi radialis 
Palmaris longus 
Flexor carpi ulnaris 



Lax part of capsule 
Annular ligament 

Tendon of biceps 
Radius 

Interosseous membrane 
Ulna 




Triceps 
tendon 



Fig.36.2 

The ligaments of the elbowjoint 
and the superior radio-ulnarjoint 



82 Upper limb 



The elbow joint (Figs 36. l and 36.2) 

• Type: synovial hinge joint. At the elbow the humeral capitulum 
articulates with the radial head, and the trochlea of the humerus with 
the trochlear notch of the ulna. Fossae immediately above the trochlea 
and capitulum admit the coronoid process of the ulna and the radial 
head, respectively, during full flexion. Similarly the olecranon fossa 
admits the olecranon process during full elbow extension. The elbow 
joint communicates with the superior radio-ulnar joint. 

• Capsule: the capsule is lax in front and behind to permit full elbow 
flexion and extension. The non-articular medial and lateral epicondyles 
are extracapsular. 

• Ligaments (Fig. 36.2): the capsule is strengthened medially and lat- 
erally by collateral ligaments. 

• The medial collateral ligament is triangular and consists of ant- 
erior, posterior and middle bands. It extends from the medial epi- 
condyle of the humerus and the olecranon to the coronoid process 
of the ulna. The ulnar nerve is adjacent to the medial collateral liga- 
ment as it passes forwards below the medial epicondyle. Owing to 
the close proximity of the ulnar nerve to the humerus it is at risk in 
many types of injury, e.g. fracture dislocations, compression and 
even during surgical explorations. 

• The lateral collateral ligament extends from the lateral epicondyle 
of the humerus to the annular ligament. The annular ligament is 
attached medially to the radial notch of the ulna and clasps, but 
does not attach to, the radial head and neck. As the ligament is not 
attached to the head this is free to rotate within the ligament. 

Elbow dislocation 

The classical injury is a posterior dislocation caused by a fall on the 
outstretched hand. It is commonest in children whilst ossification is 
incomplete. 



The superior radio-ulnar joint 

This is a pivot joint. It is formed by the articulation of the radial head 
and the radial notch of the ulna. The superior radio-ulnar joint commun- 
icates with the elbow joint. 

Movements at the elbow 

Fle.xion/extension occur at the elbow joint. Supination/pronation occur 
mostly at the superior radio-ulnar joint (in conjunction with move- 
ments at the inferior radio-ulnar joint). 

• Flexion (140°): biceps, brachialis, brachioradialis and the forearm 
flexor muscles. 

• Extension (0°): triceps and to a lesser extent anconeus. 

• Pronation (90°): pronator teres and pronator quadratus. 

• Supination (90°): biceps is the most powerful supinator. This move- 
ment is afforded by the insertion of the muscle on the posterior aspect 
of the radial tuberosity. Supinator, extensor pollicis longus and brevis 
are weaker supinators. 

The cubital fossa (Fig. 36.3) 

• This fossa is defined by: a horizontal line joining the two epi- 
condyles; the medial border of brachioradialis; and the lateral border of 
pronator teres. Thejtoor of the fossa consists of brachialis muscle and 
the overlying roo/ of superficial fascia. The median cubital vein runs in 
the superficial fascia and connects the basilic to cephalic veins. 

• Within the fossa the biceps tendon can be palpated. Medial to this lie 
the brachial artery and the median nerve. 

• The radial and ulnar nerves lie outside the cubital fossa. The radial 
nerve passes anterior to the lateral epicondyle between brachialis and 
brachioradialis muscles. The ulnar nerve winds behind the medial 
epicondyle. 



The elbow joint and cubital fossa 83 



37 The forearm 



Brachio- 
radialis 



Pronator 
teres 



Flexor carpi 
radialis 



Palmaris 
longus 

Flexor carpi 
ulnaris 




Fig.37.1 

The superficial, intermediate and 



Medial epicondyle 



Flexor digitorum 
profundus 
Flexor digitorum 
superficialis 

Radial head 

Flexor pollicis 
longus 



Pronator 
q^uadratus 



layers of the front of the forearm 



Posterior 

interosseous 

nerve 




Superficial 
radial nerve 



Fig.37.2 

The main arteries and nerves 
of the front of the forearm 



EJrachial artery 

Common flexor 
origin 

Tendon of biceps 
Ulnar artery 
Ulnar nerve 

Supinator 
Pronator teres 

Flexor digitorum 
superficialis 
Dorsal branch of 
ulnar (cutaneous) 

Radial artery 
Flexor pollicis longus 
Median nerve 
Pronator q^uadratus 



Palmaris longus 
tendon 



Flexorcarpi ulnaris 
Anconeus 




Extensor digitorum 

Extensor carpi ulnaris 
Extensor digiti minimi 
Extensor carpi radialis 
longusand brevis 
Posterior border of ulna 

Abductor pollicis longus 
and extensor pollicis brevis 
Extensor retinaculum 
Extensor pollicis longus 

First dorsal interosseous 



Fig.37.3 

The muscles of the superficial and deep layers 
of the back of the forearm and the radial nerve 



Anatomical 
snuffbox 



EJranchesto 
carpaljoints 




Radial nerve 

Superficial branch 

Supinator 

Deep (posterior 
interosseous) branch 

Abductor pollicis longus 

Extensor pollicis longus 
Extensor pollicis brevis 
Superficial branch 
Dorsal tubercle of radius 
Tendons of snuffbox 

Cutaneous branches 
to digits 



84 Upper limb 



The forearm is enclosed in deep fascia whiicii is continuous witli tliat of 
tfie arm. It is firmly attached to the periosteum of the subcutaneous bor- 
der of the ulna. Together with the interosseous membrane this divides 
the forearm into anterior and posterior compartments each possessing 
its own muscles and arterial and nervous supplies. The superficial veins 
and cutaneous sensory nerves course in the subcutaneous tissue 
superficial to the deep fascia. 

The interosseous membrane 

• The interosseous membrane unites the interosseous borders of the 
radius and ulna. The fibres of this tough membrane run obliquely down- 
wards and medially. A downwards force (e.g. fall on the outstretched 
hand) is transmitted from the radius to the ulna and from here to the 
humerus and shoulder. 

• The interosseous membrane provides attachment for neighbouring 
muscles. 

The contents of the anterior (flexor) compartment of 
the forearm 

• Muscles (Fig. 37.1): the muscles within this compartment are con- 
sidered in superficial, intermediate and deep layers. All of the muscles 
of the sitpeificial group and part of flexor digitorum supeificialis arise 
from the common flexor origin on the medial epicondyle of the 
humerus. With the exceptions oi flexor carpi ulnaris and the ulnar half 



of flexor digitorum profundus, all of the muscles of the anterior com- 
partment are supplied by the median nerve or its anterior interosseous 
branch (see Muscle index, p. 162). 

• Arteries (Fig. 37.2): ulnar artery and its anterior interosseous branch 
(via the common interosseous artery); radial artery. 

• Nerve supply (Fig. 37.2): median nerve and its anterior interosseous 
branch; ulnar nerve; superficial radial nerve. 

The contents of the posterior fascial (extensor) 
compartment of the forearm 

• Muscles (Fig. 37.1): brachioradialis and extensor carpi radialis 
longus arise separately from the lateral supracondylar ridge of the 
humerus. They are innervated by the radial nerve. The remaining 
extensor muscles are considered in superficial and deep layers which 
are innervated by Xhe posterior interosseous branch of the radial nerve. 
The muscles of the superficial layer arise from the common extensor 
origin on the lateral epicondyle of the humerus. The muscles of the 
deep layer arise from the backs of the radius, ulna and interosseous 
membrane (see Muscle index, p. 162). 

• Arteries: posterior interosseous artery (branch of the common 
interosseous artery). 

• Nerve supply: posterior interosseous nerve (branch of the radial 
nerve) (Fig. 37.3). 



The forearm 85 



38 The carpal tunnel and joints of the wrist and hand 



Thenar - 
muscles 

Flexor — 



carpi radial 

Flexor pollic 

longus 

Trapezium 

Trapezoid 




Ulna nerve and artery 
Hypothenar muscles 

Flexor retinaculum 
Median nerve 

Tendons of flexor 
digitorum superficialis 

Tendons of flexor 
digitorum profundus 

Hamate 



Capitate 



Fig.36.1 

A diagrammatic cross-section through the carpal tunnel 



Radius 




metacarpal 



Fig.36.3 

The wrist and carpal joints 



Ulna 

Disc of 
fibrocartilage 
Midcarpal 
joint 

Articular 
cartilage 




Flexor retinaculum 

Occasional 
communication 



Fig.36.2 

The synovial sheaths of the flexor tendons 



Cephalic 
vein 



Dorsal tubercle of radius 
Extensor pollicis longus 
Scaphoid 



First dorsal interosseous 

Extensor expansion 




Radial 
artery 

Abductor 
pollicus longus 
Fig.36.4 

The anatomical snuffbox 



86 Upper limb 



The flexor retinaculum and carpal tunnel (Fig. 38. i) 

The carpal tunnel is formed by the carpal bones and the overlying flexor 
retinaculum. It is through this tunnel that most, but not all, of the fore- 
arm tendons and the median nerve pass. The flexor retinaculum is 
attached to four bony points — the pisiform, the hook of the hamate, the 
scaphoid and the trapezium. 

The carpal tunnel is narrow and no arteries or veins are transmitted 
through it for risk of potential compression. The median nerve is how- 
ever at risk of compression when the tunnel is narrowed for any reason. 
This is the carpal tunnel syndrome and results in signs of median nerve 
motor and sensory impairment. Note that the ulnar nerve and artery 
pass over the retinaculum and are thus outside the carpal tunnel. 

The synovial sheaths of the flexor tendons (Fig. 38.2) 

The diagram illustrates the arrangement of the synovial sheaths that 
surround the flexor tendons. It can be seen Ihat flexor pollicis longus 
has its own sheath and flexor digitorum superficialis and profundus 
share one which ends in the palm (except that for the little finger). 

The wrist (radiocarpal) joint (Fig. 38.3) 

• Type: the wrist is a condyloid synovial joint. The distal radius and a 
triangular disc of fibrocartilage covering the distal ulna form the prox- 
imal articulating surface. This disc is attached to the edge of the ulnar 
notch of the radius and to the base of the styloid process of the ulna and 
separates the wrist joint from the inferior radio-ulnar joint. The distal 
articulating surface is formed by the scaphoid and lunate bones with the 
triquetral participating in adduction. 

• Capsule: a defined capsule surrounds the joint. It is thickened on 
either side by the radial and ulnar collateral ligaments. 

• Nerve supply: from the anterior interosseous (median) and posterior 
interosseous (radial) nerves. 



Wrist movements 

Flexion/extension movements occurring at the wrist are accompanied 
by movements at the midcarpal joint. Of a total of 80° of wrist flexion 
the majority occurs at the midcarpal joint whereas in extension a corres- 
ponding increased amount occurs at the wrist joint. 
The muscles acting on the wrist joint include: 

• Flexion: all long muscles crossing the joint anteriorly. 

• Extension: all long muscles crossing the joint posteriorly. 

• Abduction: flexor carpi radialis and extensors carpi radialis longus 
andbrevis. 

• Adduction: flexor carpi ulnaris and extensor carpi ulnaris. 

The joints of the hand (Fig. 38.3) 

• Intercarpal joints: the midcarpal joint, located between the prox- 
imal and distal rows of carpal bones, is the most important of these as it 
participates in wrist movement (see above). 

• Carpometacarpal joints: the most important of these is the 1st car- 
pometacarpal {thumb) joint. This is a saddle-shaped joint between the 
trapezium and the 1st metacarpal. It is a condyloid synovial joint which 
is separate from others in the hand, permitting a range of movement 
similar to that of a ball and socket joint. The most important movement 
of the thumb is opposition in which the thumb is opposed to the fingers 
as in holding a pen. 

• Metacarpophalangeal joints: are synovial condyloid joints. 

• Interphalangeal joints: are synovial hinge joints. 

The anatomical snuffbox 

Figure 38.4 illustrates the boundaries and contents of the anatomical 
snuffbox. 



The carpal timnel and joints of the wrist and hand 87 



39 The hand 



Adductor pollicis 



Flexor pollicis 
longus 




Flexor pollicis brevis 

Abductor pollicis 

brevis 

Opponens pollicis 

Abductor pollicis longus 

Flexor carpi radialis 

Flexor pollicis longus — 



Fig.39.1 

The superficial muscles of the hand 



Superficial transverse 
metacarpal ligament 

Palmaraponeurosis 

Abductor digiti minimi 

Flexordigiti minimi 

Flexor retinaculum 

Pisiform 

Flexor carpi ulnaris 

Long flexor tendons 



Palmaris longus 



1st lumbrical 





Branch to 
thenar muscles 



Palmar 
cutaneous nerve 



Median nerve 



Palmardigital 
nerves 



Deep branch 



Palmar (adduct) 



Dorsal (abduct) 



Fig.39.2 

The palmar (L.) and dorsal (P.) interossei 
and their actions in abduction and adduction 



Ulnar nerve 



Fig.39.3 

The ulnar (yellow) and median (green) nerves in the hand. 

Note particularly the recurrent branch of the median nerve which supplies the thenar muscles 



Upper limb 



The palm of the hand (Fig. 39. i) 

• Skin: the skin of thie palm is bound to underlying fascia by fibrous 
bands. 

• Deep fascia: the palmar aponeurosis is a triangular layer which is 
attached to the distal border of the flexor retinaculum. Distally the 
aponeurosis splits into four slips at the bases of the fingers which blend 
with the fibrous flexor sheaths (see below). The aponeurosis provides 
firm attachment of the overlying skin with protection of the underlying 
structures. 

• Fibrous flexor sheaths: these are fibrous tunnels in which the flexor 
tendons and their synovial sheaths lie. They arise from the metacarpal 
heads and pass to the bases of the distal phalanges on the anterior aspect 
of the digits. They insert into the sides of the phalanges. These sheaths 
are lax over the joints and thick over the phalanges and hence do not 
restrict flexion. 

• Synovial flexor sheaths: these are sheaths that limit friction between 
the flexor tendons and the carpal tunnel and fibrous flexor sheaths. 

• Long flexor tendons: the tendons of flexor digitorum superficialis 
(FDS) divide into two halves at the level of the proximal phalanx and 
pass around flexor digitorum profundus (FDP) where they reunite. At 
this point they then split again to insert into the sides of the middle pha- 
lanx. FDP continues along its path to insert into the distal phalanx. 
Flexor poUicis longus (FPL) passes through the carpal tunnel in its own 
synovial sheath and inserts into the distal phalanx. The tendons of 
flexor carpi radialis, palmaris longus and flexor carpi ulnaris pass 
through the forearm and also insert in the proximal hand (see Muscle 
index, p. 162). 

Muscles of the hand (Fig. 39. i) 

• The thenar muscles: these are the short muscles of the thumb. They 
include: abductor pollicis brevis, flexor poUicis brevis, opponens pol- 
licis and adductor pollicis. 

• The hypothenar muscles: these are the short muscles of the little 
finger. They include abductor digiti minimi, flexor digiti minimi and 
opponens digiti minimi. 

• Lumbricals: these four muscles arise from the tendons of flexor digi- 
torum profundus. They insert into the radial side of each of the prox- 
imal phalanges and into the dorsal extensor expansions. The lumbricals 
serve to flex the metacarpophalangeal joints without flexing the inter- 
phalangeal joints. 

• The interosseous muscles (Fig. 39.2): these comprise eight muscles 
which arise from the shafts of the metacarpals. They are responsible for 
flexion at the metacarpophalangeal joints and extension of the interpha- 
langeal joints. They also perform abduction and adduction movements 



of the fingers. These movements occur around the middle finger hence 
adduction is the bringing together of all fingers towards the middle 
finger, abduction is moving them away from the middle finger. The 
dorsal interossei each arise from two metacarpals and insert into the 
proximal phalanges so as to provide adduction (P.AD). The dorsal 
interossei arise from only one metacarpal and are inserted into the prox- 
imal phalanges so as to provide abduction (D.AB). Note that the middle 
finger cannot be adducted (and hence has no palmar interosseous) but 
can be abducted in either direction so it has two dorsal interosseous 
insertions. 

The dorsum of the hand 

• Skin: unlike the palm of the hand the skin is thin and freely mobile 
over the underlying tendons. 

• Long extensor tendons: the four tendons of extensor digitorum 
(ED) pass under the extensor retinaculum. On the dorsum of the hand 
the ED tendon to the index finger is accompanied by the tendon of ex- 
tensor indicis. The ED tendon to the little finger is accompanied by the 
double tendon of extensor digiti minimi. The ED tendons of the little, 
ring and middle fingers are connected to each other by fibrous slips. On 
the posterior surface of each finger the extensor tendon spreads to form 
a dorsal digital expansion. This expansion is triangular shaped and at its 
apex splits into three parts: a middle slip which is attached to the base of 
the middle phalanx; and two lateral slips which converge to attach to 
the base of the distal phalanx. The base of the expansion receives the 
appropriate interossei and lumbricals. The tendons of abductor pollicis 
longus, extensor pollicis brevis and longus form the boundaries of the 
anatomical snuffbox and proceed to insert into the thumb. 

Neurovascular structures of the hand (Fig. 39.3) 

See chapters on upper limb: arteries, nerves, veins and lymphatics. 

Movements of the fingers and thumb 

The hand is required to perform a versatile range of movement extend- 
ing from a firm grasp, such as that needed to carry heavy bags, to preci- 
sion gripping such as that required to hold a pencil. For precision grips 
the thumb is used to oppose the index finger in which the interpha- 
langeal joint is extended and the metacarpophalangeal joint is flexed. 
The thumb opposition is carried out mainly by opponens pollicis whilst 
the lumbricals and interossei are responsible for maintaining flexion at 
the metacarpophalangeal joints and extension at the interphalangeal 
joints. Since the thumb is at right angles to the plane of the fingers, 
abduction of the thumb is a movement away from the plane of the palm. 
This is used in testing the integrity of the median nerve (abductor poUicis). 



The hand 89 



40 Surface anatomy of the upper limb 




Pectoralis major 



Latissimusdorsi 
and teres major 

Serratus 
anterior 



Cephalic vein 
iSiceps bracliii 

Biceps tendon 
Aponeurosis - 



Basilic vein 



Fig.40.1 

The axilla with the arm fully abducted 





Fig.40.3 

Strong contraction of the pectoral 
muscles produced by adduction 





^H 


^^^H 




4 .^H 


/J" 


i^^H 



Flexor carpi radialis 
Palmaris longus 
Flexor carpi ulnaris 



Fig.40.4 

The visible tendons at the front of the wrist. 

Palmaris longus is a guide to the position of the median nerve 



Fig.40.2 

The biceps tendon and aponeurosis which are 
a guide to the positions of the brachial artery 
and the median nerve at the elbow 



Deltopectoral triangle 

Clavicular head 
Sternocostal head 



of pectoralis major 




Extensor pollicis longus 
Extensor pollicis brevis 
_Abductor pollicis longus 



Fig.40.5 

The anatomical snuffbox. 
Details are shown in Fig.36.4 



90 Upper limb 



Bones and joints 

• Vertebrae: if a finger is passed down the posterior neck in the mid- 
line the first bony structure palpated is the spinous process of the 7th 
cervical vertebra (vertebra prominens) — the first six spinous processes 
are covered by the Hgamentiim michae. 

• Scapula: the acromion process can be palpated as a lateral extension 
of the spine of the scapula. The spine, superior angle, inferior angle 
and medial border are palpable posteriorly. The coracoid process can 
be palpated below the clavicle anteriorly within the lateral part of the 
deltopectoral triangle (Fig 40.1). 

• Clavicle: is subcutaneous and therefore palpable throughout its 
length. 

• Humerus: the head is palpable in the axilla with the shoulder 
abducted. The lesser tuberosity can be felt lateral to the coracoid pro- 
cess. When the arm is externally and internally rotated the lesser 
tuberosity can be felt moving next to the fixed coracoid process. 

• Elbow: the medial and lateral epicondyles of the humerus and ole- 
cranon process of the ulna can be palpated in line when the elbow is 
extended. With the elbow flexed they form a triangle. This assumes 
importance clinically in differentiating supracondylar fractures of the 
humerus, where the 'triangle' is preserved, from elbow dislocations 
where the olecranon comes into line with the epicondyles. 

• Radius: the radial head can be felt in a hollow distal to the lateral 
epicondyle on the posterolateral aspect of the extended elbow. The 
head can be felt rotating when the forearm is pronated and supinated. 

• Ulna: the posterior border is subcutaneous and therefore palpable. 

• Wrist: the styloid processes of the radius and ulna are palpable. The 
dorsal tubercle (of Lister) can be felt on the posterior aspect of the dis- 
tal radius. 

• Hand: the pisiform can be palpated at the base of the hypothenar 
eminence. The hook of the hamate can be felt on deep palpation in the 
hypothenar eminence just distal to the pisiform. The scaphoid bone can 
be felt within the anatomical snuffbox (Fig, 40.5). 

The soft tissues 

• Axilla: the anterior axillary fold (formed by the lateral border of pec- 
toralis major) and the posterior axillary fold (formed by latissimus dorsi 
as it passes around the lower border of teres major) are easily palpable 
(Fig. 40.1). 

• Pectoralis major: contracts strongly during arm adduction (Fig. 
40.3); this is useful in the examination of breast lumps. 

• Breast: the base of the breast overlaps the 2nd to 6th ribs and extends 
from the sternum to the mid-axillary line. The nipple (in males) usually 
overlies the 4th intercostal space. 



• Anterior wrist: the proximal transverse crease corresponds to the 
level of the wrist joint. The distal transverse crease lies at the level of 
the proximal border of the flexor retinaculum. 

• Anatomical snuffbox: the boundaries are formed medially by ex- 
tensor pollicis longus and laterally by the tendons of abductor pollicis 
longus and extensor pollicis brevis. 

Vessels 

• The subclavian artery can be felt pulsating as it crosses the 1 st rib. 

• The brachial artery bifurcates into radial and ulnar branches at the 
level of the neck of the radius. The brachial pulse is felt by pressing lat- 
erally at a point medial to the bicipital tendon (Fig. 40.2). This is the 
pulse used when taking blood pressure measurements. 

• At the wrist the radial artery courses on the radial side of flexor carpi 
radialis (Fig. 40.4) and the ulnar artery and nerve course on the radial 
side of flexor carpi ulnaris. The pulses of both are easily felt at these 
points. The radial artery can also be felt in the anatomical snuffbox. 

• The superficial palmar arch is impalpable and reaches as far as the 
proximal palmar crease. The deep palmar arch reaches a point approx- 
imately one fingerbreadth proximal to the superficial arch. 

• The dorsal venous network (on the dorsum of the hand) drains later- 
ally into the cephalic vein and medially into the basilic. These veins can 
be identified in most lean subjects. The median cubital vein is usually 
visible in the cubital fossa. 

Nerves 

The idnar nerve can usually be rolled as it courses behind the medial 
epicondyle— an important point when considering surgical approaches 
to the elbow and fractures of the medial epicondyle. 

The surface markings of impalpable nerves must be known for safe 
surgical incisions. These correspond to: 

• Axillary nerve: winds around behind the surgical neck of the 
humerus. 

• Radial nerve: crosses from medial to lateral behind the humeral 
shaft at its midpoint. 

• Posterior interosseous branch (of radial nerve): winds around the 
radius three fingerbreadths distal to the head of the radius. 

• Median nerve (at the wrist) : lies in the midline, just lateral to the ten- 
don of palmaris longus. 

• Ulnar nerve (at the wrist): lies immediately medial to the ulnar 
artery. 



Surface anatomy of the upper limb 9 1 



41 The osteology of the lower limb 



Greater trochanter 
Head 

Intertrochanteric - 
line 

Lesser 

trochanter 



Patellar surface 



Trochanteric fossa 




Nutrient foramina 
Quadrate tubercle 

Intertrochanteric 

crest 

Gluteal tuberosity 

Spiral line 



Linea aspera 



Popliteal surface 

Adductor 
tubercle 



Medial epicondyle 



PI- 41 1 Intercondylar fossa 

The femur, anterior and posterior views 
and the lower end from below 



Anterior border 



Lateral 
surface 




Posterior border 
Anterior border 



Lateral 
surface 




Anterior surface 
Medial border 
Posterior surface 



Anterior surface 
Medial border 
Posterior surface 

Medial crest 

Posterior surface 



Fosterior border 
Fig.41.3 

Diagram to explain the borders and surfaces 
of the fibula (see text) 



Medial condyle 
Head of fibula 
Tubercle 



Lateral surface 
Anterior border 
Medial surface 



Medial malleolus 
Lateral malleolus 




Intercondyle eminence 
Epiphyseal line 



-Soleal line 



-Vertical line 

- Interosseous membrane 



Talus 

Sustentaculum tali 
Attachment of 
tendo calcaneus 



Fig.41.2 

The front and backof the tibia, fibula and ankle region. 

The interosseous membrane and its openings are also shown 




Peroneal nerve 

Fibular collateral ligament 

Tendon of biceps (cut) 



Superficial peroneal nerve 
Deep peroneal nerve 



Fig.41.4 

The knee viewed from the lateral side 
showing the common peroneal nerve 



92 Lower limb 



The femur (Fig. 41.1) 

The femur is the longest bone in the body. It has the following charac- 
teristic features: 

• The femoral head articulates with the acetabulum of the hip bone at 
the hip joint. It extends from the femoral neck and is rounded, smooth 
and covered with articular cartilage. This configuration permits a wide 
range of movement. The head faces medially, upwards and forwards 
into the acetabulum. The, fovea is the central depression on the head to 
which the Ugamentum teres is attached. 

• The femoral neck forms an angle of 125° with the femoral shaft. 
Pathological lessening or widening of the angle is termed coxa vara 
and coxa valga deformity, respectively. 

• The femoral shaft constitutes the length of the bone. At its upper end 
it carries the greater trochanter and, posteromedially, the lesser 
trochanter. Anteriorly the rough trochanteric line, and posteriorly the 
smooth trochanteric crest, demarcate the junction between the shaft 
and neck. The linea aspera is the crest seen running longitudinally 
along the posterior surface of the femur splitting in the lower portion 
into the supracondylar lines. The medial supracondylar line terminates 
at the adductor tubercle. 

• The lower end of the femur comprises the medial and iatersdfemoral 
condyles. These bear the articular surfaces for articulation with the tibia 
at the knee joint. The lateral condyle is more prominent than the medial. 
This prevents lateral displacement of the patella. The condyles are sep- 
arated posteriorly by a deep intercondylar notch. Anteriorly the lower 
femoral aspect is smooth for articulation with the posterior surface of 
the patella. 

The tibia (Fig. 41.2) 

The tibia serves to transfer weight from the femur to the talus. It has the 
following characteristics: 

• The flattened upper end of the tibia — the tibial plateau — comprises 
medial and lateral tibial condyles for articulation with the respective 
femoral condyles. In contrast to the femoral condyles, the medial tibial 
condyle is the larger of the two. 

• The intercondylar area is the space between the tibial condyles on 
which can be seen two projections— the medial and lateral intercondy- 
lar tubercles. Together these constitute the intercondylar eminence. 
The horns of the lateral meniscus are attached close to either side of the 
eminence. 

• On the anterior upper shaft the tibial tuberosity is easily identifiable. 
This is the site of insertion of the Ugamentum patellae. 

• The shaft is triangular in cross-section. It has anterior, medial and lat- 
eral borders and posterior, lateral and medial surfaces. 

• The anterior border and medial surface of the shaft are subcutaneous 
throughout its length. For this reason the tibial shaft is the commonest 
site for open fractures. 



• On the posterior surface of the shaft an oblique line — the soleal 
//ne— demarcates the tibial origin of soleus. Popliteus inserts into the 
triangular area above the soleal line. 

• The fibula articulates with the tibia superiorly at an articular facet 
on the postero-inferior aspect of the lateral condyle — the superior 
tibiofibular joint (synovial). 

• The fibular notch is situated laterally on the lower end of the tibia for 
articulation with the fibula at the inferior tibiofibular joint (fibrous). 

• The tibia projects inferiorly as the medial malleolus. It constitutes the 
medial part of the mortice that stabilizes the talus. The medial malleolus 
is grooved posteriorly for the passage of the tendon of tibialis posterior. 

The fibula (Fig. 41.2) 

The fibula does not form part of the knee joint and does not participate 
in weight transmission. The main functions of the fibula are to provide 
origin for muscles and to participate in the ankle joint. It has the follow- 
ing characteristic features: 

• The styloid process is a prominence on the fibular head onto which 
the tendon of biceps is inserted (around the lateral collateral ligament) 
(Fig. 41.4). 

• The fibular neck separates the head from the fibular shaft. The com- 
mon peroneal nerve winds around the neck prior to dividing into 
superficial and deep branches. This nerve is subject to injury in fibular 
neck fractures with resulting footdrop (Fig. 41 .4). 

• The fibula is triangular in cross-section. It has anterior, medial 
(interosseous) and posterior borders with anterior, lateral and posterior 
surfaces. The medial crest is on the posterior surface (Fig. 41.3). 

• The lower end of the fibula constitutes the lateral malleolus. This is 
the lateral part of the mortice that stabilizes the talus. It bears a smooth 
medial surface for articulation with the talus. The posterior aspect of 
the malleolus is grooved for the passage of the tendons of peroneus 
longus and brevis. The lateral malleolus projects further downwards 
than the medial malleolus. 

The patella 

• The ligamentum patellae, which is attached to the apex of the patella 
and the tibial tuberosity, is the true insertion of the quadriceps and the 
patella is thus a sesamoid bone (the largest in the body). This arrange- 
ment constitutes the extensor mechanism. Injiuies can occur to any 
part of the mechanism due to forcible quadriceps contraction, e.g. rup- 
tured quadriceps expansion, rupture of the ligamentum patellae or 
avulsion of the tibial tuberosity. 

• The posterior surface of the patella is smooth and covered with articu- 
lar cartilage. It is divided into a large lateral and a smaller medial facet 
for articulation with the femoral condyles. 

Bones of the foot 

Seep. 114. 



The osteology of the lower limb 93 



42 The arteries of the lower limb 



Superficial — 

circumflex 

iliac 

Femoral nerve ■ 



Lateral — 
circumflex 



Perforating 
arteries 



Genicular — 
arteries 
to knee joint 



Peroneal 



Deep peroneal - 
nerve 

Arcuate 



1^ 



m 



fQ/ 



■ Superficial epigastric 
(to abdominal wall) 

■ Femoral 

■ Superficial external pudendal 

■ Deep external pudendal 

■ Femoral sheath 

■ Femoral vein 

■ Profunda femoris 

■ Medial circumflex 



■ Gap in adductor magnus 



■ Popliteal 
■Soleusarch 



■ Posterior tibial 



-Anterior tibial 



■ Extensor retinaculum 



■ Dorsalis pedis 



■ Passes into sole to form 
deep plantar arch 

■ First dorsal metatarsal 



Fig.42.1 

The course and major branches of the femoral artery 



Anastomosis 
with dorsal 
artery 

Medial 

plantar artery 



Abductor 
hallucis 




Plantar metatarsal 
artery 

Deep plantararch 



Lateral plantar 
artery 

Flexor digitorum 
accessorius 



Fig.42.2 

The medial and lateral plantar arteries 




Stenosis 
Profunda femoris 

Right femoral artery 



Fig.42.3 

An angiogram of the lower limbs showing stenosis 
of the femoral artery on the right side. 
(The profunda is often known as the deep femoral 
and the continuation of the femoral artery as the 
superficial femoral) 



94 Lower limb 



The femoral artery 

• Course: the femoral artery commences as a continuation of the ex- 
ternal iliac artery behind the inguinal hgament at the mid-inguinal point. 
In the groin the femoral vein lies immediately medial to the artery and 
both are enclosed in the femoral sheath. In contrast, the femoral nerve 
lies immediately lateral to the femoral sheath. The femoral artery 
descends the thigh to pass under sartorius and then through the adductor 
(Hunter's) canal to become the popliteal artery. 

• Branches: 

• Branches in the upper part of the femoral triangle— four 
branches are given off which supply the superficial tissues of the 
lower abdominal wall and perineum (see Fig. 44.1). 

• Profunda femoris — arises from the lateral side of the femoral 
artery 4 cm below the inguinal ligament. Near its origin it gives rise 
to media! and lateral circumflex femoral branches. These con- 
tribute to the trochanteric and cruciate anastomoses (see below). 
The profunda descends deep to adductor longus in the medial com- 
partment of the thigh and gives rise to four perforating branches. 
These circle the femur posteriorly perforating, and supplying, all 
muscles in their path. The profunda and perforating branches ulti- 
mately anastomose with the genicular branches of the popliteal 
artery. 

The trochanteric anastomosis 

This arterial anastomosis is formed by branches from the medial and 
lateral circumflex femoral, the superior gluteal and, usually, the in- 
ferior gluteal arteries. It lies close to the trochanteric fossa and pro- 
vides branches that ascend the femoral neck beneath the retinacular 
fibres of the capsule to supply the femoral head. 

The cruciate anastomosis 

This anastomosis constitutes a collateral supply. It is formed by: the 
transverse branches of the medial and lateral circumflex femoral arter- 
ies, the descending branch of the inferior gluteal artery and the ascend- 
ing branch of the 1 st perforating branch of the profunda. 

The popliteal artery 

• Course: the femoral artery continues as the popliteal artery as it 
passes through the hiatus in adductor magnus to enter the popliteal 
space. From above, it descends on the posterior surface of the femur, 
the capsule of the knee joint and then on the fascia overlying popliteus 
to pass under the fibrous arch of soleus where it bifurcates into anterior 
andposterior tibial arteries. In the fossa it is the deepest structure, ren- 
dering it difficult to feel its pulsations. The popliteal vein crosses the 
artery superficially and the tibial nerve crosses from lateral to medial 
over the vein. The peroneal branch of the posterior tibial may arise 
early to form the popliteal trifurcation. 

• Branches: muscular, sural and five genicular arteries are given off. 
The last form a rich anastomosis around the knee. 

The anteriortibial artery 

• Course: the anterior tibial artery passes anteriorly from its origin, 
accompanied by its venae comitantes, over the upper border of the inter- 
osseous membrane and then descends over the anterior surface of the 
membrane giving off muscular branches to the extensor compartment 
of the leg. The artery crosses the front of the ankle joint midway be- 



tween the malleoli where it becomes the dorsalis pedis artery. Tibialis 
anterior and extensor digitorum longus flank the artery throughout its 
course on its medial and lateral sides, respectively. Extensor hallucis 
longus commences on the lateral side but crosses the artery to lie 
medial by the end of its course. The dorsalis pedis artery passes on the 
dorsum of the foot to the level of the base of the metatarsals and then 
between the two heads of the first dorsal interosseous muscle to gain 
access to the sole and complete the deep plantar arch. Prior to passing to 
the sole it gives off the 1st dorsal metatarsal branch and via an arcuate 
branch the three remaining dorsal metatarsal branches (Fig. 42. 1). 

• Branches of the anterior tibial artery include: muscular and 
malleolar branches. 

The posterior tibial artery 

• Course: the posterior tibial artery arises as a terminal branch of the 
popliteal artery. It is accompanied by its venae comitantes and supplies 
the flexor compartment of the leg. Approximately midway down the 
calf the tibial nerve crosses behind the artery from medial to lateral. 
The artery ultimately passes behind the medial malleolus to divide into 
medial and lateral plantar arteries under the flexor retinaculum. The 
latter branches gain access to the sole deep to abductor hallucis. 
Posterior to the medial malleolus the structures which can be 
identified— from front to back— are: tibialis posterior, flexor digitorum 
longus, posterior tibial artery and venae comitantes, the tibial nerve and 
flexor hallucis longus. 

• Branches: 

• Peroneal artery— this artery usually arises from the posterior tibial 
artery approximately 2.5 cm along its length. It courses between 
tibialis posterior and flexor hallucis longus and supplies the per- 
oneal (lateral) compartment of the leg. It ends by dividing into a 
perforating branch that pierces the interosseous membrane and a 
lateral calcaneal branch. 

• Other branches — the posterior tibial artery gives rise to nutrient 
and muscular branches throughout its course. 

• Lateral plantar artery — passes between flexor accessorius and 
flexor digitorum brevis to the lateral aspect of the sole where it 
divides into superficial and deep branches. The deep branch runs 
between the 3rd and 4th muscle layers of the sole to continue as the 
deep plantar arch which is completed by the termination of the 
dorsalis pedis artery. The arch gives rise to plantar metatarsal 
branches which supply the toes (Fig. 42.2). 

• Medial plantar artery — runs on the medial aspect of the sole and 
sends branches which join with the plantar metatarsal branches of 
the lateral plantar artery to supply the toes. 

Peripheral vascular disease (Fig. 42.3) 

Atheroma causes narrowing of the peripheral arteries with a con- 
sequent reduction in flow. Whilst flow may be adequate for tissue 
perfusion at rest, exercise causes pain due to ischaemia (intermittent 
claudication). When symptoms are intolerable, pain is present at 
rest or ischaemic ulceration has occurred, arterial reconstruction is 
required. Reconstruction is peiformed using either the patient' s own 
saphenous vein or a synthetic graft (Dacron or PTFE) to bypass the 
occlusion. Disease which is limited in extent may be suitable for inter- 
ventional procedures such as percutaneous transluminal angioplasty 
(PTA) or stent insertion. 



The arteries of the lower limb 95 



43 The veins and lymphatics of the lower limb 



From lower abdomen 



Inguinal lymph nodes 
From perineum 



and gluteal region 



Great saphenous vein 




Fig.43.1 

The superficial veins and lymphatics of the lower limb. 
The arrows indicate the direction of lymph flow 



Vein linking great 
and small saphenous 
veins 



Popliteal lymph nodes 



Short saphenous vein 




Superficial epigastric 
Inguinal ligament 
Pubic tubercle 
ym- Edge of saphenous opening 
^^ Femoral vein 

^- Deep fascia of thigh 

Superficial external 
pudendal 

Great saphenous vein 



Fig.43.2 

The termination of the great saphenous vein 




Fig.43.3 

Lymphoedemaof the lower limb 



96 Lower limb 



The superficial veins of ttie lower limb (Fig. 43. i) 

The superficial system comprises tlie great and small saphenous veins. 
Tliese are of utmost clinical importance as they are predisposed 
towards becoming varicose and consequently often require surgery. 
They are also the commonly used conduits for coronary artery surgery. 

• The great saphenous vein arises from the medial end of the dorsal 
venous network on the foot. It passes anterior to the medial malleolus, 
along the anteromedial aspect of the calf (with the saphenous nerve), 
migrates posteriorly to a handbreadth behind patella at the knee and 
then courses forward to ascend the anteromedial thigh. It pierces the 
cribriform fascia to drain into the femoral vein at the saphenous open- 
ing. The terminal part of the great saphenous vein usually receives 
superficial tributaries from the external genitalia and the lower abdom- 
inal wall (Fig. 43.2). At surgery these help to distinguish the saphenous 
from the femoral vein as the only tributary draining into the latter is the 
saphenous vein. Anteromedial and posterolateral femoral {lateral 
accessory) tributaries, from the medial and lateral aspects of the thigh, 
also sometimes drain into the great saphenous vein below the saphen- 
ous opening. 

The great saphenous vein is connected to the deep venous system at 
multiple levels by perforating veins. These usually occur above and 
below the medial malleolus, in the gaiter area, in the mid-calf region, 
below the knee and one long connection in the lower thigh. The valves 
in the perforators are directed inwards so that blood flows from 
superficial to deep systems from where it can be pumped upwards 
assisted by the muscular contractions of the calf muscles. The deep sys- 
tem is consequently at higher pressure than the superficial and thus, 
should the valves in the perforators become incompetent, the increased 
pressure is transmitted to the superficial system and these veins become 
varicose. 

• The small saphenous vein arises from the lateral end of the dorsal 
venous network on the foot. It passes behind the lateral malleolus and 
over the back of the calf to pierce the deep fascia in an inconstant posi- 
tion to drain into the popliteal vein. 

The deep veins of the lower limb 

The deep veins of the calf are the venae comitantes of the anterior and 
posterior tibial arteries which go on to become the popliteal and 
femoral veins. The deep veins form an extensive network within the 



posterior compartment of the calf— the soleal plexus from which blood 
is assisted upwards against gravitational forces by muscular contrac- 
tion during exercise. Failure of this 'muscle pump' to work efficiently, 
as occurs, for instance, during long flights in cramped conditions, may 
cause deep venous thrombosis (DVT). 

Varicose veins 

These are classified as: 

• Primary: due to inherent valve dysfunction. 

• Secondary: due to impedance of flow within the deep venous circula- 
tion. These can occur in pregnancy or due to obstruction caused by 
pelvic tumours or previous deep venous thrombosis. 

In both cases the superficial veins are subjected to increased pres- 
sure and become varicose. 

The lymphatics of the lower limb (Fig. 43. i) 

The lymph nodes of the groin are arranged into superficial and deep 
groups. The superficial inguinal group lie in the superficial fascia and 
are arranged in two chains: 

• Longitudinal chain : these lie along the terminal portion of the saphen- 
ous vein. They receive lymph from the majority of the superficial tis- 
sues of the lower limb. 

• Horizontal chain: these lie parallel to the inguinal ligament. They 
receive lymph from the superficial tissues of the: lower trunk below the 
level of the umbilicus, the buttock, the external genitalia and the lower 
half of the anal canal. The superficial nodes drain into the deep nodes 
through the saphenous opening in the deep fascia. 

The deep inguinal nodes are situated medial to the femoral vein. 
They are usually three in number. These nodes receive lymph from all 
of the tissues deep to the fascia lata of the lower limb. In addition they 
also receive lymph from the skin and superficial tissues of the heel and 
lateral aspect of the foot by way of the popliteal nodes. The deep nodes 
convey lymph to external iliac and thence to the para-aortic nodes. 

Obstruction of lymphatics results in lymphoedema (Fig. 43.3). This 
can be congenital, due to aberrant lymphatic formation, or acquired 
such as post radiotherapy or following certain infections. In develop- 
ing countries infection with Filaria bancrofti is a significant cause of 
lymphoedema that can progress to massive proportions requiring limb 
reduction or even amputation. 



The veins and lymphatics of the lower limb 97 



44 The nerves of the lower limb I 



Anterior superior 
iliac spine 
Lateral cutaneous 
nerve of thigh 

lliacus 




Lateral cutaneous 
nerve of thigh 

lliacus 

Femoral nerve 

Nerve to sartorius 

Tensor fasciae latae 
To vastus lateralis 
Psoas 

To vastus intermedius 
and rectus femoris 

Sartorius 

Intermediate 

cutaneous nerve 

of thigh 

(Skin of front of thigh) 

Rectus femoris 



Inguinal ligament 

External oblique aponeurosis 

Femoral nerve 

Femoral artery 

Femoral vein 

Femoral canal 



i^^^ — Lacunar ligament 
Pubic tubercle 
Pectineus 



Fig.44.1 

The femoral nerve and its major branches. 
The upper diagram shows the structures 
that pass underthe inguinal ligament 



Inguinal ligament 

Pubic tubercle 
To pectineus 
Pectineus 
Adductor longus 
Femoral vein 
Great saphenous vein 
Femoral artery 
Saphenous nerve 
To vastus medialis 
Medial cutaneous 
nerve of thigh 
(5kin ofmediai thigh) 
Gracilis 



Adductor 
longus 



Deep fascia 
(5kin of mediai ieg 
and foot) 




Obturator 
extern us 

Pectineus 

Posterior 
division 

Adductor brevis 
Anterior division 



Gracilis 

Branch to 
knee joint 



Fig.44.2 

The anterior and posterior divisions 
of the obturator nerve 



Lower limb 



The lumbar plexus (T12-L5) (see Fig. 21.1) 

See Chapter 21. 

• Origins: from the anterior primary rami of T12-L5. 

• Course: the majority of the branches of the plexus pass through the 
substance of psoas major and emerge at its lateral border except for the 
genitofemoral and obturator nerves. 

• Branches: 

• Intra-abdominal branches — these are described in Chapter 2 1 . 

• Femoral nerve (L2,3,4) — see below. 

• Obturator nerve (L2,3,4)— see below. 

• Lateral cutaneous nerve of the thigh (L2,3) — crosses the iliac 
fossa over iliacus and passes under the lateral part of the inguinal 
ligament to enter the superficial tissue of the lateral thigh which it 
supplies. Obese patients sometimes describe paraesthesiae over the 
lateral thigh. This is termed meralgia paraesthetica and results from 
compression of this nerve as it passes under the inguinal ligament. 

The femoral nerve (L2,3,4) (Fig. 44.1) 

• Origins: the posterior divisions of the anterior primary rami of 
L2,3,4. 

• Course: the femoral nerve traverses psoas to emerge at its lateral 
border. It descends through the iliac fossa to pass under the inguinal 
ligament. At this point it lies on iliacus, which it supplies, and is situ- 
ated immediately lateral to the femoral sheath. It branches within the 
femoral triangle only a short distance (5 cm) beyond the inguinal liga- 
ment. The lateral circumflex femoral artery passes through these 
branches to divide them into superficial and deep divisions: 



• Superficial division— consists of medial and intermediate cutan- 
eous branches, which supply the skin over the anterior and medial 
aspects of the thigh, and two muscular branches. The latter supply 
sartorius and pectineus. 

• Deep division— consists of four muscular branches which supply 
the components of quadriceps femoris and one cutaneous nerve — 
the saphenous nerve. The latter nerve is the only branch to extend 
beyond the knee. It pierces the deep fascia overlying the adductor 
canal and descends through the leg, accompanied by the great 
saphenous vein, to supply the skin over the medial aspect of the leg 
and foot. 

The obturator nerve (L2,3,4) (Fig. 44.2) 

• Origins: the anterior divisions of the anterior primary rami of 
L2,3,4. 

• Course: the obturator nerve emerges at the medial border of psoas 
(cf. other nerves which traverse psoas to emerge at the lateral border). 
It passes over the pelvic brim to pass through the upper aspect of the 
obturator foramen with other obturator vessels. In the obturator notch 
it divides into anterior and posterior divisions which pass in front 
of and behind adductor brevis to supply the muscles of the adductor 
compartment: 

• Anterior division— gives rise to an articular branch to the hip joint 
as well as muscular branches to adductor longus, brevis and gra- 
cilis. It terminates by supplying the skin of the medial aspect of the 
thigh. 

• Posterior division — supplies muscular branches to obturator 
externus, adductor brevis and magnus and obturator externus as 
well as an articular branch to the knee. 



The nerves of the lower limb I 



45 The nerves of the lower limb II 



Lumbosacral trunk — 

Superior gluteal nerve 

(L4,5,S1) 

Inferior gluteal nerve 

(L 5, 5 1,2) 

Nerve to q^uadratus 

femoris (L4, 5, SI) 

To obturator 

internus (L 5, SI, 2) 
Sciatic 



Posterior cutaneous 
nerve of thigh (S 1, 2, 3) 
Perforating cutaneous 
nerve (S 2, 3) 

Pudendal 

(S 2, 3, 4) 

Fig.45.1 

The sacral plexus 





Deep branch 

Superficial 
branch 

Medial plantar 
Lateral plantar 



,(0 



SIV 

sv 

Coccygeal 



Tibial nerve (L 4, 5, S 1, 2, 3) 

Muscular branches to: 

plantaris 

popliteus 

gastrocnemius 

soleus 
Kneejoint 



Sural nerve 

(skin of lower lateral calf, 
lateral foot and little toe) 

Muscular branches to: ^ 
flexor digitorum longus 
flexor hallucis longus 
tibialis posterior 



Fig.45.3 

The medial and lateral plantar nerves 



Medial plantar 
(L4,5) 



Lateral plantar 
(SI, 2) 



Fig.45.2 

The sciatic nerve and its major branches 

Sciatic nerve (L 4-S 3) 

Nerve to q^uadratus femoris (L 4, 5, S 1) 

Nerve to obturator internus (L 5, S 1, 2) 

Muscular branches to hamstrings 
(semitendinosus, semimembranosus 
and biceps femoris) and hamstring 
part of adductor magnus 



Common peroneal nerve (L 4-S 2) 

Lateral cutaneous nerve of the calf 
Kneejoint 

■ Sural communicating nerve 

■ Superficial peroneal nerve 
(supplies: 

peroneus longus, brevis, and skin) 
Deep peroneal nerve 
(supplies: 

extensor digitorum longus 

tibialis anterior 

extensor hallucis longus 

peroneus tertius 

extensor digitorum brevis 

and skin of the 1st dorsal web space) 



Deep peroneal 

Superficial 

peroneal 




1 00 Lower limb 



The sacral plexus (L4-S4) (Fig. 45. i) 

• Origins: from the anterior primary rami of L4-S4. 

• Course: the sacral nerves emerge through the anterior sacral foram- 
ina. The nerves unite, and are joined by the lumbosacral trunk (L4,5), 
anterior to piriformis. 

• Branches: the branches of the sacral plexus include: 

• The superior gluteal nerve (L4,5,S1) — arises from the roots of the 
sciatic nerve and passes through the greater sciatic foramen above 
the upper border of piriformis. In the gluteal region it runs below 
the middle gluteal line between gluteus medius and minimis (both 
of which it supplies) before terminating in the substance of tensor 
fasciae latae. 

• The inferior gluteal nerve (L5,S1,2) — arises from the roots of the 
sciatic nerve and passes through the greater sciatic foramen below 
piriformis. In the gluteal region it penetrates and supplies gluteus 
maximus. 

• The posterior cutaneous nerve of the thigh (SI, 2, 3) — passes 
through the greater sciatic foramen below piriformis. Its branches 
supply the skin of the scrotum, buttock and back of the thigh up to 
the knee. 

• The perforating cutaneous nerve (S2, 3) — perforates gluteus 
maximus to supply the skin of the buttock. 

• The pudendal nerve (S2, 3, 4) — passes briefly into the gluteal 
region by passing out of the greater sciatic foramen below pirifor- 
mis over the sacrospinous ligament and passes back into the pelvis 
through the lesser sciatic foramen. It runs forwards in the pudendal 
(Alcock's) canal and gives off its inferior rectal branch in the 
ischio-rectal fossa. It continues its course to the perineum and 
divides into dorsal and perineal branches that pass deep and 
superficial to the urogenital diaphragm, respectively. 

• The sciatic nerve— see below. 

The sciatic nerve (L4-S3) (Fig. 45.2) 

• Origins: anterior primary rami of L4,5, SI, S2,S3. 

• Course: the sciatic nerve passes through the greater sciatic foramen 
below piriformis under the cover of gluteus maximus. In the gluteal 
region it passes over the superior gemellus, obturator internus and in- 
ferior gemellus and then over quadratus femoris and adductor magnus 
in the thigh as it descends in the midline. The sciatic divides into its 
terminal branches, the tibial and common peroneal nerves, usually just 
below the mid-thigh, although a higher division is not uncommon. 

• Branches: 

• Muscular branches — to the hamstrings and the ischial part of 
adductor magnus. 

• Nerve to obturator internus (L5,S1,2) — supplies obturator inter- 
nus and the superior gemellus. 

• Nerve to quadratus femoris (L4,5,S1) — supplies quadratus 
femoris and the inferior gemellus. 

• Tibial nerve — see below. 

• Common peroneal nerve — see below. 



The tibial nerve (L4-S3) (Fig. 45.2) 

• Origins: it is a terminal branch of the sciatic nerve. 

• Course: it traverses the popliteal fossa over the popliteal vein and 
artery from the lateral to medial side. It leaves the popliteal fossa by 
passing under the fibrous arch of soleus and, in the leg, descends with 
the posterior tibial artery under the cover of this muscle. The nerve 
crosses the posterior tibial artery from medial to lateral in the mid-calf 
and, together with the artery, passes behind the medial malleolus and 
then under the flexor retinaculum where it divides into its terminal 
branches, the medial and lateral plantar nerves. 

• Main branches: 

• Genicular branches — to the knee joint. 

• Muscular branches — to plantaris, soleus, gastrocnemius and the 
deep muscles at the back of the leg. 

• Sural nerve — arises in the popliteal fossa and is joined by the sural 
communicating branch of the deep peroneal nerve. It pierces the 
deep fascia in the calf and descends subcutaneously with the small 
saphenous vein. It passes behind the lateral malleolus and under the 
flexor retinaculum to divide into its cutaneous terminal branches 
which supply the skin of the lower lateral calf, foot and little toe. 

• Medial plantar nerve (L4,5) (Fig. 45.3) — runs with the medial 
plantar artery between abductor hallucis and flexor digitorum bre- 
vis. It sends four motor branches and a cutaneous supply to the 
medial i'/i digits. 

• Lateral plantar nerve (SI, 2) (Fig. 45.3) — runs with the lateral 
plantar artery to the base of the 5th metatarsal where it divides into 
superficial and deep branches. These collectively supply the skin of 
the lateral 1 '/i digits and the remaining muscles of the sole. 

The common peroneal nerve (L4-S2) (Fig. 45.2) 

• Origin : a terminal branch of the sciatic nerve. 

• Course: it passes along the medial border of the biceps tendon along 
the superolateral margin of the popliteal fossa. The nerve winds around 
the neck of the fibula and, in the substance of peroneus longus, it divides 
into its terminal branches, the superficial and deep peroneal nerves. 

• Branches: 

• Genicular branches to the knee joint. 

• Lateral cutaneous nerve of the calf. 

• A sural communicating branch. 

• Superficial peroneal nerve (L5,S1,2) — this branch runs in and 
supplies the muscles of the lateral (peroneal) compartment of the 
leg. In addition it supplies the skin over the lateral lower two-thirds 
of the leg and the whole of the dorsum of the foot except for the 
area between the 1st and 2nd toes, which is supplied by the deep 
peroneal nerve. 

• Deep peroneal nerve (L4,5,S1,2) — runs with the anterior tibial 
vessels over the interosseous membrane into the anterior compart- 
ment of the leg and then over the ankle to the dorsum of the foot. It 
supplies all of the muscles of the anterior compartment as well as 
providing a cutaneous supply to the area between the 1 st and 2nd toes. 



The nerves of the lower limb II 101 



46 The hip joint and gluteal region 



Anterior inferior iliac spine 

Iliofemoral (Bigelow's) ligament 

Greater trochanter 
Pubofemoral ligament B+h 

Lesser trochanter 



Fig.46.1 

The front of the hipjoint 




Origins of rectus femoris 
Iliofemoral ligament 
Fat pad 

Articular cartilage 




Ligamentum 
teres 

Pubofemoral 
ligament 



Transverse 
ligament 



Ischiofemoral 
ligament 

Obturator 

membrane 
Fig.46.2 

The structures around the acetabulum 



Labrum 

acetabulare 

Cut edge of 

capsular 

ligament 

Sacrospinous 

ligament 



Sacrotuberous 
ligament 



The hip joint (Figs 46.1, 46.2 and 46.5) 

• Type: the hip is a synovial ball and socket joint. The articulation is 
between the rounded femoral head and the acetabulum which, like the 
shoulder, is deepened at its margins by a fibrocartilaginous rim— the 
labrutn acetabulare. The central and inferior parts of the acetabulum 
are devoid of articulating surface. This region is termed the acetabular 
notch from which the ligamentum teres passes to the fovea on the 
femoral head. The inferior margin below the acetabular notch is com- 
pleted by the transverse acetabular ligament. 

• Capsule: thecapsuleof the hipjoint is attached above to the acetabu- 
lar margin, including the transverse acetabular ligament. The capsule 
attaches to the femur anteriorly at the trochanteric line and to the bases 
of the trochanters. Posteriorly the capsule attaches to the femur at a 
higher level— approximately 1 cm above the trochanteric crest. The 
capsular fibres are reflected from the lower attachment upwards on the 



femoral neck as retinacula. These fibres are of extreme importance as 
they carry with them a blood supply to the femoral head. 
• Stability: the stability of the hip is dependent predominantly on bony 
factors. Ligamentous stability is provided by three ligaments: 

(a) Iliofemoral ligament (Bigelow's ligament)— is inverted, Yshaped 
and strong. It arises from the anterior inferior iliac spine and 
inserts at either end of the trochanteric line. This ligament pre- 
vents hyperextension at the hip. 

(b) Pubofemoral ligament— arises from the iliopubic junction and 
passes to the capsule over the trochanteric line where it attaches. 

(c) Ischiofemoral ligament — fibres arise from the ischium and some 
encircle laterally to attach to the base of the greater trochanter. 
The majority of the fibres, however, spiral and blend with the 
capsule around the neck of the femur — the zona orbicularis. 



102 Lower limb 




Gluteus medius 

Aponeurosis covering 
erector spinae 

Tensor fasciae latae 
Gluteus maximus 



lliotibial tract 

Gracilis 

Adductor magnus 
Semitendinosus 
Biceps femoris 
Vastus lateralis 



Fig.46.3 

The superficial muscles of the gluteal region 



• Synovium: the synovial membrane lines the capsule of the hip joint 
and is reflected back along the femoral neck. It invests the ligamentum 
teres as a sleeve and attaches to the articular margins. A psoas bursa 
occurs in 10% of the population. This is an outpouching of synovial 
membrane through a defect in the anterior capsular wall under the 
psoas tendon. 

• Blood supply (Fig. 46.6): the femoral head derives its blood supply 
from three main sources: 

1 Vessels which pass along the neck with the capsular retinacula and 
enter the head through large foramina at the base of the head. 



These are derived from branches of the circumflex femoral arteries 
via the cruciate and trochanteric anastomoses. This is the most 
important supply in the adult. 

2 Vessels in the ligamentum teres which enter the head through 
small foramina in the fovea. These are derived from branches of 
the obturator artery. 

3 Through the diaphysis via nutrient femoral vessels. 

• Nerve supply: is from branches of the femoral, sciatic and obturator 
nerves. 



The hip joint and gluteal region 103 



Gluteus medius 
Gluteus maximus 

Femoral insertion 
of gluteus maximus 

Internal pudendal nerve 
and artery 

Vastus lateralis 
Biceps femoris 
Semimembranosus 
Semitendinosus 




Gluteus medius 

Gluteus minimus 

Superior gluteal artery and nerve 

Inferior gluteal nerve 

Piriformis 

Obturator internus and gemelli 

Inferior gluteal artery 

Quadratusfemoris 

Posterior cutaneous nerve of thigh 

Sciatic nerve 



Adductor magnus 

Opening in adductor magnus 
Biceps (short head) 
Biceps (long head) 

Sciatic nerve 

Semimembranosus tendon 



Gastrocnemius 



Fig. 46.4 

The deeper structures in the gluteal region after the removal of gluteus maximus and medius 



Hip movements 

A wide range of movement is possible at tlie liip due to tlie ball and 
socket articulation. 

• Flexion (0-120°): iliacus and psoas predominantly. Rectus femoris. 
sartorius and pectineus to a lesser degree. 

• Extension (0-20°): gluteus maximus and the hamstrings. 

• Adduction (0-30°): adductor magnus, longus and brevis predomin- 
antly. Gracilis and pectineus to a lesser degree. 



• Abduction (0-45°): gluteus medius, gluteus minimis and tensor fas- 
ciae latae. 

• Lateral rotation (0-45°): piriformis, obturators, the gemelli, 
quadratus femoris and gluteus maximus. 

• Medial rotation (0-45°): tensor fasciae latae, gluteus medius and 
gluteus minimis. 

• Circumduction: this is a combination of all movements utilizing all 
muscle groups mentioned. 



104 Lower limb 



Iliolumbar 
ligament 



Body weight 



Long and short 
posterior ligaments 



Greater sciatic 
foramen 

Sacrospinous 
ligament 
Sacrotuberous 
ligament 




Arteries from capsule in retinacula 



Artery in 
ligamentum teres 



Sacrotuberous 
ligament 



Ischiofemoral ligament 



Fig.46.5 

The ligaments of the back of the hip. 

The smaller diagram shows how the sacrotuberous and 

sacrospinous ligaments resist rotation of the sacrum 




Subcapital 
Cervical 
13a sal 
Pertrochanteric 



-Intracapsular 
-Extracapsular 



Fig.46.6 

The terminology of fractures of the neck of the femur. 
Fractures near the head can cause avascular 
necrosis because of the disruption of the arterial 
supply to the head 



The fractured neck of femur (Fig. 46.6) 

Femoral neck fractures are common following falls among the elderly 
osteoporotic population. Fractures in this region present a consider- 
able risk of avascular necrosis if the fracture line is intracapsidar as 
the retinacula, which carry the main arterial supply, are torn. In con- 
trast, extracapsular femoral neck fractures present no risk of avascular 
necrosis. 

If the fracture components are not impacted the usual clinical pre- 
sentation is that of shortening and external rotation of the affected 
limb. This occurs as the adductors, hamstrings and rectus femoris pull 
upwards on the distal fragment whilst piriformis, the gemelli, obtiw- 
ators, gluteus maximus and gravity produce lateral rotation. 

Tlie gluteal region (Figs 46.3 and 46.4) 

Tlie gluteal region is limited above by the iliac crest and below by the 
transverse skin crease — the gluteal fold. The fold occurs as the overly- 
ing skin is bound to the underlying deep fascia and not, as is often 
thought, by the contour of gluteus maximus. The greater and lesser 



sciatic foramina are formed by the pelvis and sacrotuberous and 
sacrospinous ligaments (Fig. 46.5). Through these, structures pass 
from the pelvis to the gluteal region. 

Contents of the gluteal region (Fig. 46.4) 

• Muscles: of the gluteal region include: gluteus maximus, gluteus 
medius, gluteus minimis, tensor fasciae latae, piriformis, gemellus 
superior, gemellus inferior, obtiwator internus and quadratus femoris 
(see Muscle index, p. 164). 

• Nerves: of the gluteal region include the: sciatic nerve (L4,5,Sl-3), 
posterior cutaneous nerve of the thigh, superior (L4,5,S1,2) and in- 
ferior gluteal (L5,S1,2) nei'ves, nerve to quadratus femoris (L4,5,S1) 
and the pudendal nerve (S2-4). 

• Arteries: of the gluteal region include the: superior and inferior 
gluteal arteries. These anastomose with the medial and lateral femoral 
circumflex arteries, and the first perforating branch of the profunda, to 
form the trochanteric and cruciate anastomoses, respectively. 



The hip joint and gluteal region 105 



47 The thigh 



Tensor fasciae 
latae 



Rectus femoris 

Vastus lateralis 
lliotibial tract — 




Patellar — 
retinacula 



Fig.47.1 

The muscles of the front of the thigh. 
The femoral triangle is outlined 



lliacus 

Femoral triangle 
Inguinal ligament 

Psoas tendon 
Pectineus 
Adductor longus 
Gracilis 
Sartorius 

Vastus medialis 



Ligamentum patellae 



Diaphragm - 

Right crus - 

Quadratus 
lumborum 



Psoas major - 
lliacus 



Inguinal ligament 
Pectineus 



Adductor longus 



Adductor magnus 



Opening inadducto 
magnus (for passage 
of femoral vessels 
to popliteal fossa) 



Fig.47.2 

Psoas, lliacus and the adductor 
group of muscles 




The thigh is divided into flexor, extensor and adductor compartments. 
The membranous superficial fascia of the abdominal wall fuses to the 
fascia lata, the deep fascia of the lower limb, at the skin crease of the 
hip joint just below the inguinal ligament. 

The deep fascia of the thigh (fascia lata) 

This layer of strong fascia covers the thigh. It is attached above to the 
inguinal ligament and bony margins of the pelvis and below to the tibial 
condyles, head of the fibula and patella. Three fascial septa pass from 
the deep surface of the fascia lata to insert onto the linea aspera of the 
femur and consequently divide the thigh into three compartments. 



On the lateral side the fascia lata is condensed to form the iliotihial 
tract (Fig. 47.4). The tract is attached above to the iliac crest and 
receives the insertions of tensor fasciae latae and three-quarters of glu- 
teus maximus. These muscles are also enveloped in deep fascia. The lli- 
otibial tract inserts into the lateral condyle of the tibia. 

The saphenous opening is a gap in the deep fascia which is filled with 
loose connective tissue— the cribriform fascia . The lateral border of the 
opening, the falciform margin, curves in front of the femoral vessels 
whereas on the medial side it curves behind to attach to the iliopectineal 
line (Fig. 43.1). The great saphenous vein pierces the cribriform fascia 
to drain into the femoral vein. Superficial branches of the femoral artery 
and lymphatics are also transmitted through the saphenous opening. 



1 06 Lower limb 



Nerve to vastu 



Saphenous nerve 

Sartorius 
Femoral vessels 

Great saphenous vein 
Adductor longus 
Profunda vessels 

Gracilis 



Adductor brevis 



Adductor magnus 




Rectus femoris 
Vastus lateralis 
Vastus medialis 
lliotibial tract 
Vastus intermedius 

Sciatic nerve 

Short 

heads of biceps 
Long 

Semimembranosus 
Semitendinosus 



Fig.47.3 

A section through the thigh to show the adductor (subsartorial) canal 



The superficial fascia of tlie tliigli 

Contents of the subcutaneous tissue include: 

• Nerves: tiie femoral branch of the genitofemoral nerve (p. 51), the 
medial, intermediate (branches of the femoral nerve, p. 99) and lateral 
femoral cutaneous nerves (L2,3, p. 99) and branches of the obturator 
nerve (p. 99) supply the skin of the anterior thigh. The back of the thigh 
receives its sensory supply from the posterior cutaneous nerve of the 
thigh. 

• Superficial arteries: these include the four superficial branches of 
the femoral artery: the superficial circumflex iliac artery, superficial 
epigastric artery, superficial external pudendal artery and the deep 
external pudendal artery. 

• Superficial veins and lymphatics: venous tributaries of the anterior 
thigh drain into the great saphenous vein whilst some in the lower pos- 
terior thigh drain into the popliteal vein. The great saphenous vein is 
also accompanied by large lymphatics which pass to the superficial 
inguinal nodes and, from there, through the cribriform fascia to the 
deep inguinal nodes. 

Tlie femoral triangle (Figs 44.1 and47.i) 

The boundaries of the femoral triangle are: the inguinal ligament 
above, the medial border of sartorius and the media! border of adductor 
longus. 

• Tlie floor consists of: adductor longus, pectineus, psoas tendon and 
iliacus (see Muscle index, p. 165). 



• The roof consists of: fascia lata. The saphenous opening is in the 
upper part of the triangle. 

• The contents include (from lateral to medial) the: femoral nerve, 
artery, vein and their branches and tributaries. Thefemoral canal is situ- 
ated medial to the femoral vein. Transversalis fascia and psoas fascia 
fuse and evaginate to form thefemoral sheath below the inguinal liga- 
ment. The sheath encloses the femoral artery, vein and canal but the 
femoral nerve lies outside on its lateral aspect (see Fig. 44.1). 

The contents of the anterior compartment of the thigh 

(Fig.47.3) 

• Muscles: these constitute the hip flexors and knee extensors, i.e. sar- 
torius, iliacus, psoas, pectineus and quadriceps femoris (see Muscle 
index, p. 165). 

• Arteries: the femoral artery and its branches (p. 95). 

• Veins: the femoral vein is a continuation of the popliteal vein as 
it passes through the hiatus in adductor magnus. It receives its main 
tributary— the great saphenous vein — through the saphenous opening. 

• Lymphatics: from the anterior compartment pass to the deep inguinal 
lymph nodes which lie along the terminal part of the femoral vein. 

• Nerves: the femoral nerve (L2,3,4, p. 99) divides a short distance 
below the inguinal ligament into anterior and posterior divisions. Only 
the saphenous branch passes beyond the knee. 



The thigh 107 



Fig.47.4 

The lateral side of the thigh. 
Note the two muscles inserted 
into the iliotibial tract 




Iliac crest 

Fascia covering gluteus medius 

Tensor fasciae latae 
Gluteus maximus 
Iliotibial tract 
Rectus femoris 

Vastus lateralis 

Biceps femoris (long head) 



The contents of the medial compartment of the thigh 

(Figs 47.2 and 47.3) 

• Muscles: these comprise tlie liip adductors: gracilis, adductor 
longiis, adductor brevis, adductor magnus and obturator externiis (a 
lateral rotator of tlie tliigli at thie liip) (see Muscle index, p. 165). 

• Arteries: profunda femoris (p. 95) as well as its medial circumflex 
femoral and perforating branches and the obturator artery. 

• Veins: profunda femoris and obturator veins. 

• Nerves: the anterior and posterior divisions of the obturator nerve 
(p. 99). 

The contents of the posterior compartment of the thigh 

(Fig. 47.3) 

• Muscles: these are the hamstrings and effect knee flexion and hip ex- 
tension. They include: biceps femoris, semitendinosus, semimembranosus 
and the hamstring part of adductor magnus (see Muscle index, p. 165). 

• Arteries: the perforating branches of profunda femoris. 

• Veins: the venae comitantes of the small arteries. 

• Nerves: the sciatic nerve (L4,5,Sl-3, p. 101). The muscles of the 
posterior compartment are supplied by the tibial component of the sci- 
atic nerve with the exception of the short head of biceps femoris which 
is supplied by the common peroneal component. 



The adductor (subsartorial or Hunter's) canal 

The adductor canal serves to transmit structures from the apex of the 
femoral triangle through the hiatus in adductor magnus into the 
popliteal fossa. It commences in the mid-portion of the thigh and is 
formed by the following walls: 

• The posterior wall: adductor longus, with adductor magnus in the 
lower part of the thigh. 

• Thelateral wall: vastus medialis. 

• The roof: thickened fascia underlying sartorius. 

The contents of the adductor canal 

These include: the femoral artery, the femoral vein which lies deep to 
the femoral artery, lymphatics, the saphenous branch of the femoral 
nerve (which passes behind sartorius to leave the canal and descends 
the lower limb with the great saphenous vein), the nerve to vastus medi- 
alis (in the upper part) and the subsartorial plexus. This plexus is 
formed by branches from the saphenous nerve (terminal branch of the 
femoral nerve, p. 99), the anterior division of the obturator nerve and 
the intermediate cutaneous nerve of the thigh (branch of the femoral 
nerve, p. 99). It supplies the skin over the medial aspect of the knee. 



108 Lower limb 



48 The knee joint and popliteal fossa 



Adductor 
magnustend 




Vastus medialis 



Tibial collatei 
ligament 



Fig.4ft.1 

Knee joint, medial aspect 



Patella 

Patellar retinaculum 

Ligamentum patellae 
Semitendinosus 
Gracilis 
Sartorius 

Lateral epicondyle 

Lateral head of — 
gastrocnemius 

Fibular collateral 
ligament 

Popliteus 

Biceps tendon 




Quadriceps 
Dotted line indicates 
the extent of the 
suprapatellar bursa 

Patella 

Lateral patellar 

retinaculum 

Cut edge of capsular 

ligament 

Lateral meniscus 

Ligamentum patellae 

lliotibial tract 



Fig.43.2 

Knee joint, lateral aspect after removal of part of the capsular ligament 




Medial head of gastrocnemius 

Tibial collateral ligament 

Posterior menisco-femoral 
ligament 

Semimembranosus tendon 

Oblic^ue popliteal ligament 
Posterior cruciate ligament 



Fig.46.3 

Knee joint, posterior aspect after removal of the capsular ligament 



Popliteal surface of femur 

Plantaris 

Lateral head of gastrocnemius 

Anterior menisco-femoral ligament 
Popliteus tendon 
Fibular collateral ligament 



The knee joint and popliteal fossa 109 



Lateral condyle 



Fibular collateral ligament 



Ligamentum patellae 




Medial condyle 
Posterior cruciate ligament 
Anterior cruciate ligament 
Medial meniscus 

Coronary ligament 
Fat 



Tibial collateral ligament 



Patella (turned back) 



Fig.45.4 

Anterior view of the flexed knee joint after d ivision of the o|_uadriceps 
and retraction of the patella 



Transverse ligament 

Anterior cruciate 
ligament 

Tibial collateral 
ligament 

Medial meniscus 




Deep infrapatellar 
bursa 

Cut edge of 
capsular ligament 

Lateral meniscus 

Fibular collateral 
ligament 

Posterior menisco- 
femoral ligament 
Tendon of popliteus 





Anterior 
cruciate ligament 



Posterior 
cruciate ligament 



Posterior cruciate ligament 



Fig.46.5 

The upper surface of the tibia and related structures. 

The dotted line indicates the synovial membrane in the vicinity of the cruciate ligaments. 

The small diagrams show how the cruciate ligaments resist forward and backward displacement of the femur 



The knee joint (Figs 48. 1-48.5) 

• Type: it is a synovial modified hinge joint whichi also permits a small 
degree of rotation. In the knee joint the femoral and tibial condyles 
articulate as does the patella and patellar surface of the femur. Note: the 
fibula does not contribute to the knee joint. 

• Capsule: the articular surfaces are covered by articular cartilage. The 
capsule is attached to the margins of the articular surfaces except anter- 
iorly where it dips downwards. In the anterior part of the capsule there 
is a large opening through which the synovial membrane is continuous 
with the suprapatellar bursa (Fig. 48.2). This bursa extends superiorly 
three fingerbreadths above the patella between the femur and quad- 
riceps. When an effusion has collected fluctuation can be elicited. 
Posteriorly the capsule communicates with another bursa under the 
medial head of gastrocnemius and often, through it, with the bursa of 
semimembranosus. Posterolaterally another opening in the capsule per- 
mits the passage of the tendon oi popliteus. 

• Extracapsular ligaments: the capsule of the knee joint is reinforced 
by ligaments. 



• The medial (tibial) collateral ligament (Figs 48.1 and 48.3)— con- 
sists of superficial and deep parts. The superficial component is 
attached above to the femoral epicondyle and below to the subcuta- 
neous surface of the tibia. The deep component is firmly attached to 
the medial meniscus. 

• The lateral (fibular) collateral ligament (Fig. 48.2)— is attached to 
the femoral epicondyle above and, along with biceps femoris, to 
the head of the fibula below. Unlike the medial collateral ligament 
it lies away from the capsule and meniscus. 

The collateral ligaments are taut in full extension and it is in this 
position that they are liable to injury when subjected to extreme val- 
gus/varus strain. 

Behind the knee the oblique popliteal ligament, a reflected exten- 
sion from the semimembranosus tendon, strengthens the capsule (Fig. 
48.3). Anteriorly the capsule is reinforced by the ligamentum patellae 
and the patellar retinacula. The latter are reflected fibrous expansions 
arising from vastus lateralis and medialis muscles which blend with the 
capsule anteriorly (Fig. 48.1). 



110 Lower limb 



Semitendinosus — 
Semimembranosus 
Gracilis 



Popliteal vein 
Popliteal artery 



Gastrocnemius 
(medial head) 

Fig.4&.6 

The right popliteal fossa 




Biceps femoris 

Tibial nerve 

Popliteal surface of femur 

Plantaris 

Common peroneal nerve 

Lateral cutaneous nerve of calf 
Sural communicating nerve 
Sural nerve 



• Intracapsular ligaments: the cruciate ligaments are enclosed 
within the knee joint (Figs 48.4 and 48.5). 

• The anterior cruciate ligament— passes from the front of the inter- 
condylar area of the tibia to the medial side of the lateral femoral 
condyle. This ligament prevents hyperextension and resists for- 
ward movement of the tibia on the femur. 

• The posterior cruciate ligament— passes from the back of the inter- 
condylar area of the tibia to the lateral side of the medial condyle. It 
becomes taut in hyperflexion and resists posterior displacement of 
the tibia on the femur. 

• The menisci (semilunar cartilages): these are crescentic fibrocarti- 
laginous 'shock absorbers' within the joint. They lie within deepened 
grooves on the articular surfaces of the tibial condyles (Fig. 48.5). The 
medial meniscus is C shaped and larger than the lateral meniscus. The 
menisci are attached to the tibial intercondylar area by their horns and 
around their periphery by small coronary ligaments. The lateral menis- 
cus is loosely attached to the tibia and connected to the femur by two 
meniscofemoral ligaments (see Fig. 48.3). 

The menisci are especially prone to flexion/rotation injuries of the 
knee. The classic medial meniscus injury occurs when a footballer 
twists the knee during running. It is a combination of external rotation 
and abduction inflexion. 

• Blood supply: is from the rich anastomosis formed by the genicular 
branches of the popliteal artery. 

• Nerve supply: is from branches of the femoral, tibial, common per- 
oneal and obturator nerves. 

Knee movements 

Flexion and extension are the principal movements at the knee. Some 
rotation is possible when the knee is flexed but is lost in extension. 



During the terminal stages of extension the large medial tibial condyle 
screws forwards onto the femoral condyle to lock the joint. Conversely, 
the first stage of flexion is unlocking the joint by internal rotation of the 
medial tibial condyle — an action performed by popliteus. 
The principal muscles acting on the knee are: 

• Extension: quadriceps femoris. 

• Flexion: predominantly the hamstrings but also gracilis, gastrocne- 
mius and sartorius. 

• Rotation: popliteus effects internal (medial) rotatory movement of 
the tibia. 

The popliteal fossa (Fig. 48.6) 

The femoral artery and vein pass through the hiatus in adductor magnus 
to enter the popliteal fossa and in so doing become the popliteal vessels. 
The popliteal fossa is rhomboidal in shape. Its boundaries are: 
the biceps tendon (superolateral) and semimembranosus reinforced 
by semitendinosus (superomedial). The medial and lateral heads of 
gastrocnemius form the inferomedial and inferolateral boundaries, 
respectively. 

• The roof consists of: deep fascia which is penetrated at an inconstant 
position by the small saphenous vein as it drains into the popliteal vein. 

• The floor consists of (from above downwards): the posterior lower 
femur, the posterior surface of the knee joint and popliteus. 

• The contents of the fossa include (from deep to superficial): the 
popliteal artery, vein and tibial nerve. The common peroneal nerve 
runs along the medial border of biceps tendon and then out of the fossa. 
Other contents include fat anA popliteal lymph nodes. 

The popliteal pulse is notoriously difficult to feel because the artery 
lies deep to other structures. Whenever a popliteal pulse is easily pal- 
pable the possibility of aneurysmal change should be considered. 



The knee joint and popliteal fossa 111 



49 The leg 



Vastus 
medialis 



Ligamentum 

patellae 

Sartorius 



Gastrocnemius 
and soleus 

Tibialis 

anterior 
Subcutaneous 
surface of tibia 




Rectus femoris 
Vastus lateralis 



Peroneus longus 
and brevis 

Extensor digitorum 

longus 

Extensor hallucis longus 

Superior and inferior 
extensor retinacula 

Extensor digitorum brevis 
Peroneus tertius 




Vastus lateralis 
Biceps femoris 

lliotibial tract 



Peroneus longus 

Soleus 

Gastrocnemius 



Peroneus brevis 
Peroneus retinaculum 
Peroneus tertius 



Fig.49.1 

The extensor (dorsiflexor) group of muscles 



Fig.49.2 

The lateral side of the leg and foot 



Gastrocnemius 
(medial head) 

Medial ligament 
of kneejoint 

Popliteus 




Flexor digitorum 
longus 

Tibialis posterior 

Flexor hallucis — 
longus 

Fig.49.3 

The superficial muscles of the calf 



Plantaris 
Gastrocnemius 
(lateral head) 

Head of fibula 



Soleus 
Gastrocnemius 

Peroneus longus 
Tendo calcaneus 




Extensor 

digitorum longus 

Extensor 
hallucis longus 

Peroneus 
brevis 

Peroneus 
longus 

Fibula' 
Flexor 
hallucis longus 

Soleus 

Gastrocnemius 

Fig.49.4 

Cross-section through the leg, to be studied in conjunction with Fig.41.4 



Tibialis anterior 

Deep peroneal nerve 
and anteriortibial 
vessels 

Tibia 

Tibialis posterior 

(U— Great saphenous 
vein 

Flexor digitorum 
longus 

Tibial vessels and 
nerve 

Small saphenous 
vein 



112 Lower limb 



Within thie leg thiere are tliree predominant muscle groups: extensor, 
peroneal and flexor. Each of these groups has an individual blood and 
nerve supply. 

Students are often confused about the description of movements 
of the foot. Extension of the foot (dorsiflexion) refers to lifting the 
toes and the ball of the foot upwards. Conversely, foot flexion (plan- 
tarflexion) is the opposing action. 

The deep fascia of the leg 

The deep fascia of the leg is continuous above with the deep fascia of 
the thigh. It envelops the leg and fuses with the periosteum of the tibia 
at the anterior and medial borders. Other fascial septa, and the inter- 
osseous membrane, divide the leg into four compartments: extensor, 
peroneal, superficial and deep flexor. 

F allowing fractures of the leg, oedema within one or more compart- 
ments can lead to obstruction to blood flow with consequent infarction 
of tissue — the 'compartment syndrome' . When this occurs immediate 
decompression (fasciotomy) of all four compartments is necessary. 

The superior and inferiortibiofibular joints 

These are, respectively, synovial and fibrous joints between the tibia 
and fibula at their proximal and distal ends. 

The interosseous membrane (Fig. 49.4) 

The interosseous borders of the tibia and fibula are connected by a 
strong sheet of connective tissue— the interosseous membrane. The 
fibres of the membrane run obliquely downwards from tibia to fibula. 
Its function is to bind together the bones of the leg as well as providing 
a surface for muscle attachment. 

The extensor aspects of the leg and dorsum of the foot 

(Figs 49. land 49 .4) 

The extensor group consists of four muscles in the leg (see below) and 
extensor digitorum brevis in the foot. These muscles dorsiflex the foot. 
The contents of the extensor compartment of the leg are as follows: 

• Muscles: tibialis anterior, extensor hallucis longus, extensor digito- 
rum longus and peroneus tertius (unimportant in function) (see Muscle 
index, p. 166). 

• Artery: the anterior tibial artery (p. 95) and its venae comitantes 
form the vascular supply of the extensor compartment. The artery con- 
tinues as the dorsalis pedis artery in the foot. 

• Nerves: the deep peroneal nerve (p. 101) supplies all of the muscles 
of the extensor compartment. Injury to this nerve results in the inability 
to dorsiflex the foot— footdrop. 



The extensor r etinacula (Fig . 49 . 1 ) 

These are thickenings of the deep fascia of the leg. They serve to stabil- 
ize the underlying extensor tendons. 

• The superior extensor retinaculum: is a transverse band attached to 
the anterior borders of the tibia and fibula. 

• The inferior extensor retinaculum: is Y shaped. Medially the two 
limbs attach to the medial malleolus and the plantar aponeurosis and 
laterally the single limb is attached to the calcaneus. 

The peroneal compartment of the leg (Figs 49 .2 and 49 .4) 

This compartment consists of two muscles — peroneus longus and 
brevis. These muscles are the predominant foot everters. The contents 
of the peroneal compartment include: 

• Muscles: peroneus longus and brevis (see Muscle index, p. 166). 

• Artery: the peroneal artery (p. 95). 

• Nerve: the superficial peroneal nerve (p. 101). 

Peroneal retinacula (Fig. 49.2) 

The superior peroneal retinaculum is a thickening of deep fascia 
attached from the lateral malleolus to the calcaneus. The inferior per- 
oneal retinaculum is a similar band of fascia which is continuous with 
the inferior extensor retinaculum. The tendons of peroneus longus and 
brevis pass in their synovial sheaths beneath. 

The flexor aspect of the leg (Fig. 49.3) 

The flexor muscles of the calf are considered in two groups — superficial 
and deep flexor groups. All flexor muscles of the calf receive their 
nerve and arterial supplies from the tibial nerve and the posterior tibial 
artery, respectively. 

The contents of the flexor compartment of the calf include: 

• Superficial flexor muscle group: gastrocnemius, soleus and plan- 
tar is (the last is rudimentary in humans). Note that all of these muscles 
are inserted into the middle third of the posterior surface of the cal- 
caneus via the tendocalcaneus {Achilles tendon). A small bursa (the 
retrocalcaneal bursa) occupies the space between the upper third of the 
posterior surface of the calcaneus and the Achilles tendon. Within 
soleus, and to a lesser extent gastrocnemius, there is an extensive 
venous plexus. These muscles act as a muscle pump squeezing venous 
blood upwards during their contraction. It is in these veins that deep 
venous thromboses readily occur post surgery in the immobile patient. 

• Deep ffexor muscle group: tibialis posterior, flexor digitorum 
longus, flexor hallucis longus (see Muscle index, p. 166). 

• Artery: posterior tibial artery (p. 95). 

• "Nerye: tibial nerve {p. lOl). 



The leg 113 



50 The ankle and foot I 



Deltoid 
ligament 

Tibialis — 
posterior 



Flexor — 
digitorum 
longus 

Flexor — 



hallucis longus 




Interosseous 

tibiofibular 

ligament 

Interosseous 
talocalcaneal 
ligament 

Calcaneofibular 
ligament 

Peroneus brevis 

Peroneus longus 



Fig.50.1 

The ankle joint from behind, to show how the talus 
is held in position by ligaments between the tibia 
and fibula above and the calcaneus below 



Joints 

1. Subtalarjoint 

2. Midtarsal (talonavicular) 

3. Tarsometatarsal 

4. Metatarsophalangeal 
Calcaneus ^ Midtarsal (calcaneocuboid) 

Talus 

Sustentaculum tali 

Facet for medial malleolus 

Head of talus 
Navicular 

Tuberosity of navicular 
Medial cuneiform 

j^. ' yj y sse.^/ — First metatarsal 

Sesamoid bone 




Sinus tarsi 
Cuboid 




Facet for 

lateral 

malleolus 



Posterior 

tibiofibular 

ligament 

Posterior 
talofibular 
ligament 




tibiofibular 



bifurcate ligament 
Cuboid 
Cervical ligament 
Long plantar ligament 
Calcaneofibular ligament 
Fig.50.3 

Theanklejoint, lateral aspect after removal 
of the capsular ligament 



Fig.50.2 

The bones of the foot, medial and lateral aspects. 
The major joints are shown 



Tendo 
calcaneus 



Deltoid 
ligament 




rst 
etatarsal 



Plantar 

calcaneonavicular 
(spring) ligament 

Fig.50.4 

The ankle joint, medial aspect 



Tuberosity 
of navicular 

Long plantar ligament 



114 Lower limb 



Theankle joint (Fig. 50.1) 

• Type: the ankle is a synovial hinge joint involving the tibia, fibula 
and talus. The articular surfaces are covered with cartilage and synovial 
membrane lines the rest of the joint. 

• Capsule: the capsule encloses the articular surfaces. The capsule is 
reinforced on either side by strong collateral ligaments but is lax anter- 
iorly to permit uninhibited hinged movement. 

• Ligaments: the medial collateral (deltoid) ligament consists of a 
deep component which is a vertical band passing from the medial 
malleolus to the talus. The superficial component of this ligament is fan 
shaped and extends from the medial malleolus to (from front to back): 
the tuberosity of the navicular, the spring ligament (see below), the sus- 
tentaculum tali and the posterior tubercle of the talus (Figs 50. 1 and 50.4). 

The lateral collateral ligament consists of three bands: the anterior 
and posterior talofibular ligaments and the calcaneofibular ligament 
(Fig. 50.3). Abduction I adduction forces on the ankle can cause a 
sprain — an incomplete tear of one of the collateral ligaments. Complete 
tears of the ligaments also occur and lead to painful instability at the 
ankle joint on clinical examination. Severe forces on the ankle joint can 
result in fracture or fracture dislocation. 

The movements at the ankle 

It is important to note that the inversion and eversion movements of 
the foot do not occur at the ankle joint except in full plantarflexion. 
These occur at the subtalar and midtarsal joints (see below). Only 
dorsiflexion (extension) and plantarflexion (flexion) occur at the ankle. 
The principal muscles are: 

• Dorsiflexion: tibialis anterior and to a lesser extent extensor hallucis 
longus and extensor digitorum longus. 

• Plantarflexion: gastrocnemius and soleus and to a lesser extent 
tibialis posterior, flexor hallucis longus and flexor digitorum longus. 

Thefoot bones (Fig. 50.2) 

With the exception of the metatarsals and phalanges the foot bones are 
termed collectively the tarsal bones. 

• Talus: has a body with facets on the superior, medial and lateral sur- 
faces for articulation with the tibia, medial malleolus and lateral malle- 
olus, respectively. There is a groove on the posterior surface of the 
body for the tendon of flexor hallucis longus. To the groove's lateral 
side is the posterior (lateral) tubercle, sometimes known as the os 
trigomim, as it ossifies from a separate centre to the talus. A head pro- 
jects distally which articulates with the navicular. The head is con- 
nected to the body by a neck. 

• Calcaneus: has two facets on the superior surface which participate 
in the subtalar (talocalcaneal and talocalcaneonavicular) joint. The 



posterior surface has three areas: a roughened middle part where the 
tendocalcaneus inserts; a smooth upper part which is separated from 
the tendocalcaneus by a bursa (retrocalcaneal bursa) (Fig. 50.4); and a 
lower part which is covered by a fibro-fatty pad that forms the heel. 
Medial and lateral tubercles are present on the inferior surface to which 
the plantar aponeurosis is attached. The sustentaculum tali is a distinct- 
ive projection on the medial surface which forms a shelf for the support 
of the talus. The peroneal tubercle, a small projection on the lateral sur- 
face of the calcaneus, separates the tendons of peroneus longus and 
brevis. The anterior surface has a facet for articulation with the cuboid. 

• Cuboid: has a grooved undersurface for the tendon of peroneus 
longus. 

• Navicular: has facets for the articulations with the head of the talus 
posteriorly and the three cuneiforms anteriorly. It has a tuberosity on its 
medial aspect which provides attachment for tibialis posterior. 

• Cuneiforms: there are three cuneiforms which articulate anteriorly 
with the metatarsals and posteriorly with the navicular. Their wedge- 
shape helps to maintain the transverse arch of the foot. 

• Metatarsals and phalanges: these are similar to the metacarpals and 
phalanges of the hand. Note the articulations of the heads of the 
metatarsals. The 1st metatarsal is large and is important for balance. 
The head is grooved on its inferior surface for the two sesamoid bones 
within the tendon of flexor hallucis brevis. 

Thefoot joints 

• Subtalar joint (Fig. 50.2): this compound joint comprises the talo- 
calcaneal and the talocalcaneonavicular \omii. Inversion and eversion 
movements occur at the subtalar joint. 

• The talcocalcaneal joint— is a synovial plane joint formed by the 
articulation of the upper surface of the calcaneus with the lower 
surface of the talus. 

• The talocalcaneonavicular joint— is a synovial ball and socket 
joint between the head of the talus and the sustentaculum tali, the 
spring ligament and the navicular. 

• Midtarsal joint (Fig. 50.2): is also a compound joint which con- 
tributes towards foot inversion/eversion movements. This joint is com- 
posed of the calcaneocuboid joint and the talonavicular component of 
the talocalcaneonaviculai' joint. 

• The calcaneocuboid joint— is a synovial plane joint formed 
between the anterior surface of the calcaneus and the posterior 
surface of the cuboid. 

• Other foot joints (Fig. 50.2): these include other tarsal joints, tar- 
sometatarsal (synovial plane), intermetatarsal (synovial plane), meta- 
tarsophalangeal (synovial condyloid) and interphalangeal (synovial 
hinge) joints. 



The ankle and foot I 115 



51 The ankle and foot II 



Peronei 

Superficial 
peroneal 
nerve 
(cut off) 



Extensor 
digitorum brevis 
Dorsal 
metatarsal 
arteries 




Gastrocnemius 

and soleus 

Extensor digitorum 

Tibialis anterior 

Tibia 

Extensor hallucis longus 

Extensor retinacula 



Dorsalis pedis 

Dorsalis pedis passes 
into sole 



Fig.51.1 

The structures on the front of the ankle 
and the dorsum of the foot 



Flexor hallucis 
brevis 

Abductor 

hallucis 

Flexor hallucis 

longus 

Flexor digitorum 

longus 

Plantar aponeurosis 



Flexor 

hallucis longus 

Adductoi 

hallucis 



Abductor 
hallucis 



Plantar 
aponeurosis 



Tendon of 

tibialis posterior 

Navicular 




Under-surfaceof 
spring ligament 

Sustentaculum 
tali 



Fig.51.2 

The deep ligaments of the sole of the foot 



Tendon of 
peroneus longus 

Long plantar 
ligament 




Flexor 

digitorum 

longus 



Flexor 

digitorum 

brevis 

Abductor 

digiti 

minimi 



Fig.51.3 

Thefirst layer of muscles in the sole of the foot 




2nd and 3rd lumbricals 

Abductor digiti minimi 

Flexor digiti 
minimi brevis 
Flexor digitorum 
accessorius 
Flexor digitorum 
brevis 



Sesamoid 
bones 

Abductor 
hallucis 

Flexor — 



hallucis brevis 



Tibialis 
posterior tendon 




Transverse and 
oblique heads of 
adductor 
pollucis 

Flexordigiti 
minimi brevis 



Fibrous covering 
of peroneus 
longus tendon 



Fig.51.4 

The second layer of muscles in the sole of the foot 



Fig.51.5 

The third layer of muscles in the sole of the foot 



116 Lower limb 



Ligaments of the foot 

• Spring (plantar calcaneonavicular) ligament (Fig. 51.2): runs 
from the sustentaculum tali to the tuberosity of the navicular forming a 
support for the head of the talus. 

• Bifurcate ligament: is Y shaped and runs from the anterior part of 
the calcaneus to the cuboid and navicular bones. It reinforces the 
capsule of the talocalcaneonavicular joint. 

• Long plantar ligament (Figs 51.2 and 50.3): runs from the under- 
surface of the calcaneus to the cuboid and bases of the lateral meta- 
tarsals. The ligament runs over the tendon of peroneus longus. 

• Short plantar ligament: runs from the undersurface of the calca- 
neus to the cuboid. 

• Medial and lateral (talocalcaneal) ligaments: strengthen the 
capsule of the talocalcaneal joint. 

• Interosseous talocalcaneal ligament: runs in the sinus tarsi, a 
tunnel formed by deep sulci on the talus and calcaneus. 

• Deep transverse metacarpal ligaments: join the plantar ligaments 
of the metatarsophalangeal joints of the five toes. 

The arches of the foot 

The integrity of the foot is maintained by two longitudinal (medial and 
lateral) arches and a single transverse arch. The arches are held 
together by a combination of bony, ligamentous and muscular factors 
so that standing weight is taken on the posterior part of the calcaneum 
and the metatarsal heads as a result of the integrity of the arches. 

• Medial longitudinal arch (see Fig. 50.2): comprises calcaneus, talus 
(the apex of the arch), navicular, the three cuneiforms and three medial 
metatarsals. The arch is bound together by the spring ligament, muscles 
and supported from above by tibialis anterior and posterior. 

• Lateral longitudinal arch (see Fig. 50.2): comprises calcaneus, 
cuboid and the two lateral metatarsals. The arch is bound together by 
the long and short plantar ligaments and supported from above by per- 
oneus longus and brevis. 

• Transverse arch: comprises the cuneiforms and bases of the meta- 
tarsals. The arch is bound together by the deep transverse ligament, 
plantar ligaments and the interossei. It is supported from above by per- 
oneus longus and brevis. 

The dorsum of the foot (Fig. 51. i) 

The skin of the dorsum of the foot is supplied by cutaneous branches of 
the superficial peroneal, deep peroneal, saphenous and sural nerves. 
The dorsal venous arch lies within the subcutaneous tissue overlying 
the metatarsal heads. It receives blood from most of the superficial tis- 
sues of the foot via digital and communicating branches. The great 
saphenous vein commences from the medial end of the arch and the 
small saphenous vein from the lateral end. 



Structures on the dorsum of the foot (Fig. 51.1) 

• Muscles: extensor digitorum brevis arises from the calcaneus. Other 
muscles insert on the dorsum of the foot but arise from the leg. These 
include: tibialis anterior, extensor hallucis longus, extensor digitorum 
longus, peroneus tertius and peroneus brevis. Each tendon of extensor 
digitorum longus is joined on its lateral side by a tendon from extensor 
digitorum brevis. The tendons of extensor digitorum longus and per- 
oneus tertius share a common synovial sheath whilst the other tendons 
have individual sheaths. 

• Arterial supply: is from the dorsalis pedis artery— the continuation 
of the anterior tibial artery. The dorsalis pedis ends by passing to the 
sole where it completes the plantar arch (p. 95). 

• Nerve supply: is from the deep peroneal nerve via its medial and lat- 
eral terminal branches. The latter supplies extensor digitorum brevis 
whereas the former receives cutaneous branches from the skin. 

The sole of the foot 

The sole is described as consisting of an aponeurosis and four muscle 
layers. The skin of the sole is supplied by the medial and lateral plantar 
branches of the tibial nerve. The medial calcaneal branch of the tibial 
nerve innervates a small area on the medial aspect of the heel. 

The plantar aponeurosis 

This aponeurosis lies deep to the superficial fascia of the sole and 
covers the 1st layer of muscles. It is attached to the calcaneus behind 
and sends a deep slip to each toe as well as blending superficially with 
the skin creases at the base of the toes. The slips that are sent to each toe 
split into two parts which pass on either side of the flexor tendons and 
fuse with the deep transverse metatarsal ligaments. 

The muscular layers of the sole 

• 1st layer consists of: abductor hallucis, flexor digitorum brevis and 
abductor digiti minimi (Fig. 5 1 .3). 

• 2nd layer consists of: flexor digitorum accessorius, the lumbricals 
and the tendons of flexor digitorum longus and flexor hallucis longus 
(Fig. 51.4). 

• 3rd layer consists of: flexor hallucis brevis, adductor hallucis and 
flexor digiti minimi brevis (Fig. 51.5). 

• 4th layer consists of: the dorsal and plantar interossei and the ten- 
dons of peroneus longus and tibialis posterior. 

Neurovascular structures of the sole 

• Arterial supply: is from the posterior tibial artery which divides into 
medial and lateral plantar branches. The latter branch contributes the 
major part of the deep plantar arch (p. 95). 

• Nerve supply: is from the tibial nerve which also divides into medial 
and lateral plantar branches (p. 101). 



The ankle and foot II 117 



52 Surface anatomy of the lower limb 



Position of 
deep ring 




lliacus 

Psoas 
tendon 

Pectineus 

Femoral liernia 

Tendon of adductor 
longus 



Fig.52.1 

Tlie anatomy of femoral and inguinal herniae. 
Note the relation of the deep inguinal ring 
to the inferior epigastric artery and the 
relation of the two types of hernia to the 
pubic tubercle 




Semi membranosus 

Semi tendinosus 

Short saphenous 
vein 



Fig.52.4 

Visible structures on the medial side 
of the lower limb 



Inferior epigastric 
artery 

External oblic^ue 
aponeurosis 

Lineaalba 

Superficial ring 
Inguinal hernia 

Lacunar 
(Gimbernat's) 
ligament 
Pubic tubercle 



Posterior 

tibiofibular ligament 

Posterior 




Posterior 
superior 1/3 

iliac spine 



Ischial 
tuberosity 



Injection 
area 



Greater 
trochanter 



Fig.52.2 

The surface markings of the sciatic nerve 



Flexor digitorum 
longus 

Medial malleolus 
Articular surface 
of talus 




talofibular ligament 

Calcaneofibular 

ligament 

Posterior surface 
of calcaneus 

Fig.52.3 

The structures on the medial side of the ankle 



Tibialis posterior 
Deltoid ligament 

Posterior tibial artery 
Posterior tibial nerve 

Flexor hallucis longus 




Extensor digitorum 
longus 

Tibialis anterior 



Peroneus longus 
and brevis 



Fig.52.5 

The lateral aspect of the foot to show 
the tendons that can be recognised 



118 Lower limb 



Surface landmarks around the hip and gluteal region 

• The anterior superior iliac spine is a prominent landmarlc at tiie 
anterior end of the iliac crest. 

• The greater trochanter of tlie femur lies approximately a hands- 
breadth below the iliac crest. It is made more prominent by adducting 
the hip. 

• The ischial tuberosity is covered by gluteus maximus when the hip 
is extended. It can be palpated in the lower part of the buttock with the 
hip flexed. 

• The femoral pulse (Fig. 52.1) is most easily felt halfway between 
the anterior superior iliac spine and the symphysis pubis (mid-inguinal 
point). The femoral head lies deep to the femoral artery at the mid- 
inguinal point. The femoral vein lies medial, and the femoral nerve lat- 
eral, to the artery at this point. 

• The femoral canal (Fig. 52.1) lies medial to the femoral vein within 
the femoral sheath. The sac of a femoral hernia passes through the canal 
to expand below the deep fascia. The hernial sac always lies below and 
lateral to the pubic tubercle (cf. the neck of an inguinal hernia which is 
always situated above and medial to the tubercle). The risk of strangula- 
tion is high in femoral herniae as the femoral canal is narrow and blood 
flow to viscera within the hernial sac can easily be impaired. 

• The great saphenous vein pierces the cribriform fascia in the saph- 
enous opening of the deep fascia to drain into the femoral vein 4 cm 
below and lateral to the pubic tubercle (Fig. 43.2). 

• In thin subjects the horizontal chain of superficial inguinal lymph 
nodes is palpable. It lies below and parallel to the inguinal ligament. 

• The sciatic nerve has a curved course throughout the gluteal region. 
Consider two lines — one connects the posterior superior iliac spine and 
the ischial tuberosity and the other connects the greater trochanter and 
the ischial tuberosity (Fig. 52.2). The nerve descends the thigh in the 
midline posteriorly. The division of the sciatic nerve into tibial and 
common peroneal components occurs usually at a point a handsbreadth 
above the popliteal crease but is highly variable. Sciatic nerve damage 
is occasionally caused by badly placed intramuscular injections. The 
safest site for intramuscular injection is consequently the upper outer 
quadrant of the buttock. 

• The common peroneal nerve winds superficially around the neck of 
the fibula. In thin subjects it can be palpated at this point. Footdrop can 
result from fibular neck fractures where damage to this nerve has 
occurred. 

Surface landmarks around the knee 

• The patella and ligamentum patellae are easily palpable with the 
limb extended and relaxed. The ligamentum patellae can be traced to its 
attachment at the tibial tuberosity. 

• The adductor tubercle can be felt on the medial aspect of the femur 
above the medial condyle. 

• The femoral and tibial condyles are prominent landmarks. With the 
knee in flexion the joint line, and outer edges of the menisci within, are 
palpable. The medial and lateral collateral ligaments are palpable on 
either side of the knee and can be followed to their bony attachments. 



• The subcutaneous border of the tibia is palpable throughout its 
length. 

• The fibular head is palpable laterally (Fig. 52.4). The shaft of the 
fibula is mostly covered but is subcutaneous for the terminal 10 cm. 

• The popliteal pulse is difficult to feel as it lies deep to the tibial nerve 
and popliteal vein. It is best felt by palpating in the popliteal fossa with 
the patient prone and the knee flexed. 

Surface landmarks around the ankle 

• The medial and lateral malleoli are prominent at the ankle. The lat- 
eral is more elongated and descends a little further than the medial. 

• When the foot is dorsiflexed the tendons of tibialis anterior, extensor 
hallucis longus and extensor digitorum are visible on the anterior 
aspect of the ankle and the dorsum of the foot. 

• The tendons of peroneus longus and brevis pass behind the lateral 
malleolus. 

• Passing behind the medial malleolus lie: the tendons of tibialis pos- 
terior and flexor digitorum longus, the posterior tibial artery and its 
venae comitantes, the tibial nerve and flexor hallucis longus (Fig. 
52.3). 

Surface landmarks around the foot (Fig. 52.5) 

• The head of the talus is palpable immediately anterior to the distal 
tibia. 

• The base of the 5th metatarsal is palpable on the lateral border of 
the foot. The tendon of peroneus brevis inserts onto the tuberosity on 
the base. 

• The heel is formed by the calcaneus. The tendocalcaneus {Achilles) 
is palpable above the heel. Sudden stretch of this can lead to rupture. 
When this occurs a gap in the tendon is often palpable. 

• The tuberosity of the navicular can be palpated 2.5 cm anterior to 
the medial malleolus. It receives most of the tendon of tibialis posterior. 

• The peroneal tubercle of the calcaneum can be felt 2.5 cm below 
the tip of the lateral malleolus. 

• The sustentaculum tali can be felt 2.5 cm below the medial malleo- 
lus. The tendon of tibialis posterior lies above the sustentaculum tali 
and the tendon of flexor hallucis longus winds beneath it. 

• The dorsalis pedis pulse is located on the dorsum of the foot be- 
tween the tendons of extensor hallucis longus and extensor digitorum. 

• The posterior tibial pulse is best felt halfway between the medial 
malleolus and the heel. 

• The dorsal venous arch is visible on the dorsum of the foot. The 
small saphenous vein drains the lateral end of the arch and passes pos- 
terior to the lateral malleolus to ascend the calf and drain into the 
popliteal vein. The great saphenous vein passes anterior to the medial 
malleolus to ascend the length of the lower limb and drain into the 
femoral vein. This vein can be accessed consistently by 'cutting down' 
anterior to, and above, the medial malleolus following local anaesthe- 
sia. This is used in emergency situations when intravenous access is 
difficult but required urgently. 



Surface anatomy of the lower limb 119 



53 The autonomic nervous system 




^ Visible 

ganglion 




Microscopic 
ganglion 



Sympathetic 
Parasympathetic 



Parasympathetic lOK 



Cranial 

outflow 

3,7,9,10/11 



Fig.53.1 

The different lengths of the pre- and postganglionic fibres 
of the autonomic nervous system. 
Preganglionic fibres: red 
Postganglionic fibres: green 



Visceral 
branch 



Grey 
ramus 



To blood 
vessels 
Spinal 
nerve 




Gut 



Suprarenal 
medulla 




Sympathetic 



T1 



L2 



Sacral outflow 
S2,3,4 

Cauda 
eq^uina 

Fig.53.2 

The sympathetic (right) and parasympathetic 
(left) outflows 



Sympathetic trunk 

White ramus 
-- 1 

Preganglionic fibres 
EJranch to blood vessels 
Descending branch 



Splanchnic nerve 
(preganglionic) 



Fig.53.3 

The various possible courses of the preganglionic fibres (1,2&3) 

and postganglionic fibres (A, Band C) of the sympathetic nervous system 



120 Autonomic nervous system 



The autonomic nervous system comprises two parts — tlie sympathetic 
and Ihe, parasympathetic. Tlie former initiates the 'fight or flight' reac- 
tion while the latter controls the body under more relaxed conditions. 
Both systems have synapses in peripheral ganglia but those of the sym- 
pathetic system are, for the most part, close to the spinal cord in the gan- 
glia of the sympathetic trunk whereas those of the parasympathetic 
system are mostly in the walls of the viscera themselves and are micro- 
scopic (except for the four macroscopic ganglia in the head and neck 
described below). Thus the sympathetic preganglionic fibres are re- 
latively short compared to the parasympathetic fibres (Fig. 53. 1). 

• Sympathetic outflow (Fig. 53.2): the anterior rami of spinal nerves 
Tl to L2 or 3. The fibres leave these spinal nerves as the white rami 
commimicantes and synapse in the ganglia of the sympathetic trunk. 

• Parasympathetic outflow: this comprises: 

• Cranial outflow — fibres travel as 'passengers' in the cranial nerves 
3, 7, 9 and 10/11 and synapse in one of the four macroscopic 
peripheral ganglia of the head and neck. 

• Sacral outflow — travel in sacral nerves S2 , 3 and 4. 

The sympathetic system 

• The sympathetic trunk: from the base of the skull to the tip of the 

coccyx where the two trunks join to form the ganglion impar. The trunk 
continues upwards into the carotid canal as the internal carotid nerve. 

• Superior cervical ganglion : represents the fused ganglia of CI .2,3 
and 4. 

• Middle cervical ganglion: represents the fused ganglia of C5 and 6. 

• Inferior cervical ganglion : represents the fused ganglia of C7 and 8. 
It may be fused with the ganglion of Tl to form the stellate ganglion. 

For courses of the pre- and postganglionic fibres see Fig. 53.3. 

• Preganglionic fibres: when the white (myelinated) rami reach the 
sympathetic trunk they may follow one of three different routes: 

1 They may synapse with a nerve cell in the corresponding ganglion. 

2 They may pass straight through the coiTcsponding ganglion and travel 
up or down the sympathetic trunk, to synapse in another ganglion. 

3 They may pass straight through their own ganglion, maintaining 
their preganglionic status until they synapse in one of the outlying 
ganglia such as the coeliac ganglion. One exceptional group of 
fibres even pass through the coeliac ganglion and do not synapse 
until they reach the suprarenal medulla. 

• Postganglionic fibres: after synapsing, the postganglionic fibres 
may follow one of three different routes: 



A They may pass back to the spinal nerve as a grey (unmyelinated) 

ramus and are then distributed with the branches of that nerve. 
B They may pass to adjacent arteries to form a plexus around them 
and are then distributed with the branches of the arteries. Other 
fibres leave branches of the spinal nerves later to pass to the arter- 
ies more distally. 
C They may pass directly to the viscera in distinct and sometimes 
named branches such as the cervical cardiac branches of the cer- 
vical ganglia. 
If the sympathetic trunk is divided above Tl or below L2, the head 
and neck or the lower limb will lose all sympathetic supply. 

Loss of the supply to the head and neck will produce Horner's syn- 
drome. There will be loss of sweating (anhidrosis), drooping of the 
upper eyelid (ptosis) and constriction of the pupil (myosis) on that side. 
Details of the sympathetic system in the various regions are given in 
the appropriate chapters, but Table 53.1 summarizes the autonomic 
supply to the most important regions and viscera. 

The parasympathetic system 

• The cranial outflow: 

III The oculomotor nerve carries parasympathetic fibres to the 
constrictor pupillae and the ciliary muscle, synapsing in the ciliary 
ganglion. 

VII The facial nerve carries fibres for the submandibular and sublin- 
gual glands (which synapse in the submandibular ganglion) and for the 
lacrimal gland (which synapse in the sphenopalatine ganglion). 
IX The glossopharyngeal nerve carries fibres for the parotid gland 
which synapse in the otic ganglion. 

X/XI The vagus and cranial root of the accessory carry fibres for the 
thoracic and abdominal viscera down as far as the proximal two-thirds 
of the transverse colon, where supply is taken over by the sacral out- 
flow. Synapses occur in minute ganglia in the cardiac and pulmonary 
plexuses and in the walls of the viscera. 

• The sacral outflow: 

From the sacral nerves S2, 3 and 4, fibres join the inferior hypogastric 
plexuses by means of the pelvic splanchnic nerves. They go on to 
supply the pelvic viscera, synapsing in minute ganglia in the walls of 
the viscera themselves. Some fibres climb out of the pelvis around the 
inferior mesenteric artery and supply the sigmoid and descending colon 
and the distal one third of the transverse colon. 



Table 53.1 The autonomic system. 



Region 



Origin of connector fibres 



Site of synapse 



Sympathetic 




Head and neck 


T1-T5 


Upper limb 


T2-T6 


Lower Umb 


T10-L2 


Heart 


T1-T5 


Lungs 


T2-T4 


Abdominal and pelvic 


T6-L2 


viscera 




Parasympathetic 




Head and neck 


Cranial nerves 3, 7, 9, 10 


Heart 


Cranial nerve 1 


Lungs 


Cranial nerve 1 


Abdominal and pelvic 


Cranial nerve 10 


viscera 





S2,3,4 



Cervical ganglia 

Inferior cervical and 1 st thoracic ganglia 

Lumbar and sacral ganglia 

Cervical and upper thoracic ganglia 

Upper thoracic ganglia 

Coeliac and subsidiary ganglia 



Various parasympathetic macroscopic ganglia 

Ganglia in vicinity of heart 

Ganglia in hila of lungs 

Microscopic ganglia in walls of viscera 

(down to transverse colon) 

Microscopic ganglia in walls of viscera 



The autonomic nervous system 121 



54 The skull I 



Coronal suture 



Frontal 



Parietal 



Sphenoid 
greater wing 

Ethmoid 

Lacrimal 

Nasal 

Zygomatic 

Maxilla 




Fig.54.1 

Skull, side view 



Styloid 
process 



Occipital 

External 
occipital 



protuberance 



Foramen 
transversarium 

Posterior tubercle - 
of atlas 



Fig.54.3 

Skull, posterior view 



Sq^uamous 
temporal 



Lambda 
Occipital 



External 
occipital 
protuberance 




Sagittal 
suture 

Lambda 



Superior 
nuchal line 

Inferior 
nuchal line 



Mastoid process 
Transverse process 



of atlas 
Tip of dens 
Spine of axis 



Supraorbital foramen 



Lacrimal 

Optic canal 

Superior 

orbital 

fissure 

Inferior 

orbital 

fissure 



Fig.54.2 

Skull, anterior view 



Metopic suture (uncommon) 
Position of frontal air sinus 

Frontal 

Ethmoid 

Orbital plate 
of frontal 
Sphenoid, 
lesser wing 
Sphenoid, 
greater wing 
Zygomatic 

Maxilla 



Mental foramen 
Vomer 
Infra-orbital foramen 




The skull consists of the bones of the cranium (making up the vault and 
the base) and the bones of the/ace, including the mandible. 

The bones of the cranium 

The vault of the skull 

• The vault of the skull comprises a number of flat bones, each of 
which consists of two layers of compact bone separated by a layer of 



cancellous bone (the diploe) which contains red bone marrow and a 
number of diploic veins. The bones are Ihc frontal, parietal, occipital, 
squamous temporal and the greater wing of the sphenoid. The frontal 
air sinuses are in the frontal bone just above the orbit. The bones are 
separated by sutures which hold the bones firmly together in the mature 
skull (Figs 54.1-3). Occasionally the frontal bone may be separated 
into two halves by a midline metopic suture. 



122 Head and neck 



Diploe 

Cribriform plate (ethmoid) 

Optic canal 

Sella turcica 

Greater wing 

of sphenoid 

Sc^uamous temporal 
Petrous temporal 

Arcuate eminence 



Foramen magnum 




Orbital plate of frontal 
Lesser wing of sphenoid 
Superior orbital fissure 

Foramen rotundum 
Foramen lacerum 
Foramen ovale 
Foramen spinosum 

Internal auditory meatus 
Jugular foramen 
Hypoglossal canal 

Groove for transverse sinus 



Fig.54.4 

The interior of the skull base. 

The anterior, middle and posterior cranial fossae are coloured green, red and blue respectively 



• There are a number of emissary foramina which transmit emissary 
veins. These establish a communication between the intra- and extra- 
cranial veins. 

On an X-ray of the skull there are markings which may be mistaken 
for a fracture. These are caused by (1) the middle meningeal artery, (2) 
diploic veins, or (3) the sutures, including the infrequent metopic suture. 

The interior of tlie base of tlie sliull 

The interior of the base of the skull comprises the anterior, middle and 
posterior cranial fossae (Fig. 54.4). 

The anterior cranial fossa 

• Bones: 

• Orbital plate of the frontal bone 

• Lesser wing of the sphenoid 

• Cribriform plate of the ethmoid 

• Foramina: 

• In the cribriform plate (Olfactory nerves) 

• Optic canal (Optic nerve and ophthalmic artery) 

• Other features: 

• The orbital plate of the frontal forms the roof of the orbit. 

• Lateral to the optic canals are the anterior clinoid processes. 

• The boundary between the anterior and middle cranial fossae is the 
sharp posterior edge of the lesser wing of the sphenoid. 

The middle cranial fossa 

• Bones: 

• Greater wing of the sphenoid 

• Temporal bone 

• Foramina: 

• Superior orbital fissure (Frontal, lacrimal and nasociliary branches 
of trigeminal nerve; oculomotor, trochlear and abducent nerves; 
ophthalmic veins) 



• Foramen rotundum (Maxillary branch of trigeminal nerve) 

• Foramen ovale (Mandibular branch of trigeminal nerve) 

• Foramen spinosum (Middle meningeal artery) 

• Foramen lacerum (Internal carotid artery through upper opening 
(p. 133)) 

• Other features: 

• The superior orbital fissure is between the greater and lesser wings 
of the sphenoid. 

• In the midline is the body of the sphenoid with the sella turcica on 
its upper aspect. It contains the sphenoidal air sinus. 

• The foramen lacerum is the gap between the apex of the petrous 
temporal and the body of the sphenoid. 

• The boundary between the middle and posterior cranial fossae is 
the sharp upper border of the petrous temporal bone. 

The posterior cranial fossa 

• Bones: 

• Petrous temporal (posterior surface) 

• Occipital 

• Foramina: 

• Foramen magnum (lower part of medulla, vertebral arteries, spinal 
accessory nerve) 

• Internal auditory meatus (facial and vestibulocochlear nerves, 
internal auditory artery) 

• Jugular foramen (glossopharyngeal, vagus and accessory nerves, 
internal jugular vein) 

• Hypoglossal canal (hypoglossal nerve) 

• Other featiwes: 

• The jugular foramen is the gap between the occipital and petrous 
temporal bones. 

• The inner surface of the occipital is marked by deep grooves for the 
transverse and sigmoid venous sinuses. They lead down to the 
jugular foramen. 



The skull I 123 



55 The skull II 



Incisive fossa 



Horizontal plate 
of palatine 

Vomer 




Foramen lacerum 

Tympanic plate 

Mastoid 

process 

Occipital condyle 
Foramen magnum ^ 



Fig.55.1 

The base of the skull from below 



Palatal process of maxilla 
Greater palatine foramen 

Pterygoid hamulus 
Lateral pterygoid plate 
Foramen ovale 
Foramen spinosum and 
spine of sphenoid 
Carotid canal 
Jugular foramen 



Coronold process 



Course of 
lingual nerve 




Alveolar 
part of body 

Body 

Mylohyoid line 
Fig.55.2 

The internal surface of the mandible 



Head 



Ramus 
Mandibularforamen 

Rough area for 
medial pterygoid 



The outside of the base of the skull (Fig. 55.1) 
The anterior part of the cranial base is hidden by the bones of the 
face (p. 1 25). The remainder consists of the bones that were seen in the 
middle and posterior cranial fossae but many of the foramina seen on 
the exterior are not visible inside the cranium. 

• Bones: 

• Temporal (Squamous, petrous and tympanic parts and the styloid 
process) 

• Sphenoid (body) which carries the medial and lateral pterygoid 
plates 

• Foramina: 

• Foramen magnum (already described) 

• Hypoglossal canal (already described) 

• Stylomastoid foramen (facial nerve) 

• Jugular foramen (already described) 

• Foramen lacerum (the internal carotid through its internal opening) 



• Carotid canal (internal carotid artery and sympathetic nerves) 

• Foramen spinosum (already described) 

• Foramen ovale (already described) 
Other features: 

• The area between and below the nuchal lines is for the attachment 
of the extensor muscles of the neck. 

• The occipital condyles, for articulation with the atlas, lie on either 
side of the foramen magnum. 

• The mastoid process is part of the petrous temporal and contains 
the mastoid air cells (p. 157). 

• The floor of the external auditory meatus is formed by the tym- 
panic plate of the temporal bone. 

• The carotid canal (see Fig. 59.2) turns inside the temporal bone to 
run horizontally forwards. It then opens into the posterior wall 
of the foramen lacerum before turning upwards again to enter the 
cranial cavity through the internal opening of the foramen. 



124 Head and neck 



• Behind the foramen spinosum is the spine of the sphenoid which 
lies medial to the mandibular fossa for articulation with the head of 
the mandible. 

• In front of this is the articular eminence, onto which the head of the 
mandible moves when the mouth is open. 

The bones of the face (Figs 54.2 and 55.2) 

The bones of the face are suspended below the front of the cranium and 
comprise the bones of the upper jaw, the bones around the orbit and 
nasal cavities and the mandible. 

• Bones: 

• Maxilla 

• Pterygoid plates of the sphenoid 

• Palatine 

• Zygomatic 

• Nasal 

• Frontal 

• Lacrimal 

• Bones of the orbit and nasal cavities (see below) 

• Foramina: 

• Supraorbital (Supraorbital nerve) 

• Infraorbital (Infraorbital nerve) 

• Mental (Mental nerve) 

• Greater and lesser palatine foramina (Greater and lesser palatine 
nerves) 



• Foramina of the incisive fossa (Nasopalatine nerves and vessels) 
• Other features: 

• The pterygoid plates of the sphenoid support the back of the 
maxilla. 

• Between these two bones is the pterygomaxillary fissure which 
leads into th& pterygopalatine fossa. 

• The hard palate is formed by the palatine process of the maxilla 
and the horizontal plate of the palatine . 

• The teeth are borne in the maxilla. 

• The maxilla contains the large maxillary air sinus. 

• The bones of the orbit: the orbital margins are formed by the 
frontal, zygomatic and maxillary bones. 

• The ethmoid lies between the two orbits and contains the ethmoidal 
air cells. 

• The lacrimal has a fossa for the lacrimal sac. 

• At the back of the orbit are the greater and lesser wings of the sphe- 
noid with the superior orbital fissure between them. Also the optic 
canal and the infraorbital fissure. 

• The bones of the nasal cavity are the maxilla, the inferior concha, 
the ethmoid, the vomer, the nasal septum and the perpendicular 
plate of the palatine. 

The mandible (Fig. 55.2) consists of the body and two rami. Each 
ramus divides into a coronoid process and the head, for articulation 
with the mandibular fossa. The mandibular foramen transmits the in- 
ferior alveolar nerve and vessels. 



The skull II 125 



56 Spinal nerves and cranial nerves l-IV 



Nasal Temporal 

field of vision field of vision 




Optic nerve 
Optic chiasma 
Position of pituitary 

Optic tract 



Fig.56.1 

The optic chiasma. 

Only the fibres from the nasal side of the retina 

(i.e., the temporal fields of vision) cross in the chiasma 



Superior 
oblio^ue 



Superior orbital 
fissure Cavernous 




Trochlear 
nerve 



Abducent 
nerve 



Lateral 
rectus 



Internal 
carotid 
artery 
Fig.56.3 

The trochlear and abducent nerves. 

The trochlear nerve arises from the dorsal surface of the brain 



■ Petrous 
temporal 
bone 



Supraorbital 



Infraorbital 



Mental - 



To 

levator palpebrae superioris Cavernous 

and superior rectus sinus 

Superior orbital 
fissure 



To 

medial rectus 

To *~ 

inferior rectus 

To 

inferior obi 

To < — 
sphincter pupillae 
and ciliaris 




- Parasympathetic fibres 

■ Ciliary ganglion 

■ Short ciliary nerves 



Fig.56.2 

The oculomotor nerve. 

Parasympathetic fibres are shown in orange 



Ophthalmic V 
Maxillary V 
MandibularV 




Sternomastoid 
Clavicle 



Auriculotemporal 
Greater occipital 



Lesser occipital 
Greater auricular 

Supraclavicular 

Transverse 

cutaneous 



Fig.56.4 

The main sensory nerves of the face and neck 



126 Head and neck 



The head and neck are supplied by the first four spinal and the 1 2 cra- 
nial nerves. 

The spinal nerves 

• Cl : supplies the small suboccipital muscles. Its anterior ramus joins the 
hypoglossal nerve but leaves it later to form the descendens hypoglossi. 

• C2: The posterior ramus forms the greater occipital nerve which is 
sensory to the scalp. 

• The posterior rami of C2, 3 and 4 provide muscular and sensory 
branches to the back. Their anterior rami provide muscular branches, 
including the descendens cervicalis (see hypoglossal nerve). They also 
supply sensory branches: the greater auricular, lesser occipital, an- 
terior cutaneous and the three supraclavicular nerves (Fig. 56.4). The 
greater auricular supplies the skin in the parotid region, the only sens- 
ory supply to the face which is not derived from the trigeminal. The 
others supply the skin of the neck and the upper part of the thorax. 

• The remaining cervical nerves (C5-8) join the brachial plexus. 

The cranial nerves (Figs 56.1-3) 

• I. The olfactory nerve: the cell bodies of the olfactory nerve are in 



the nasal mucosa. Their axons form the olfactory nerves which ascend 
through the cribriform plate to synapse in the olfactory bulb of the 
brain. 

• II. The optic nerve (Fig. 56.1): the eye and optic nerve develop as an 
outgrowth of the embryonic brain and the nerve is therefore enveloped 
in meninges. The cell bodies are in the retina and the axons pass back in 
the optic nerve to the optic chiasma where the axons from the nasal 
halves of the retina cross over but those from the temporal side continue 
on the same side. They then form the optic tract on each side. 

• III. The oculomotor nerve (Fig. 56.2): arises from the brain just in 
front of the pons, traverses the cavernous sinus and enters the orbit 
through the superior orbital fissure. Supplies the levator palpebrae 
superioris, superior, inferior and medial rectus muscles and the inferior 
oblique. It also carries parasympathetic fibres to the ciliary ganglion 
where the fibres synapse and then pass in the short ciliary nerves to the 
sphincter papillae and the ciliary muscles (see Chapter 69). 

• IV. The trochlear nerve (Fig. 56.3): arises from the dorsal surface 
of the brain just behind the inferior colliculus, winds round the mid- 
brain and enters the cavernous sinus. It enters the orbit through the 
superior orbital fissure and supplies the superior oblique. 



Spinal nerves and cranial nerves I-IV 1 27 



57 The trigeminal nerve (V) 



Infratrochlear 



Ethmoidal 



Nasociliary 
Long posterior 
ciliary 

Optic nerve — 




Supratrochlear 
Supraorbital 
Skin efface 

Parasympathetic 
fibres from 
sphenopalatine ganglion 

Frontal 
Lacrimal 
Superior orbital 
fissure 
Ophthalmic division 



Fig.57.1 

The course and branches of the ophthalmic division 

of the trigeminal nerve. 

Parasympathetic fibres are shown in orange 



Infra-orbital 



Sphenopalatine- 




Lacrimal gland 
Ophthalmic division 
F. rotund um 
Maxillary division 

Mandibular division 
Sphenopalatine ganglion 

Nasal branches 

Greater palatine 
Lesser palatine 
Posterior superior dental 
Incisive fossa 



Fig.57.2 

Thecourseand branches of the maxillary division of the trigeminal nerve. 
Parasympathetic fibres are shown in orange 



Foramen ovale 
Buccal 




Lingual 



Deep temporal (to temporalis) 

Auriculotemporal 

Otic ganglion 

Muscular branches 
Parotid gland 

Chorda tympani 
Inferioralveolar 



Submandibular ganglion 
Mylohyoid nerve 
Submandibulargland 



Fig.57.3 

Thecourseand main branches of the mandibular division of the trigeminal nerve. 
The fibres of the chorda tympani are shown in yellow 



128 Head and neck 



The trigeminal nerve (Figs 56.4 and 57.1-3) arises from the brain at the 
side of the pons by a motor and a sensory root. The sensory root carries 
the trigeminal ganglion which consists of the cell bodies of the sensory 
axons and lies in a depression on the petrous temporal bone. It then 
divides into ophthalmic, maxillary and mandibular divisions. The 
motor root forms part of the mandibular division. 

(a) The ophthalmic division (Fig. 57.1) 

This traverses the cavernous sinus and enters the orbit via the superior 
orbital fissure where it divides into frontal, lacrimal and nasociliary 
branches. The frontal nerve lies just under the roof of the orbit and 
divides into supraorbital and supratrochlear nerves which emerge 
from the orbit and supply the front of the scalp. The lacrimal nerve lies 
laterally and supplies the skin of the eyelids and face. It also carries 
parasympathetic secretomotor fibres from the sphenopalatine ganglion 
to the lacrimal gland. The nasociliary nerve crosses the optic nerve and 
runs along the medial wall of the orbit to emerge onto the face as the 
infratrochlear nerve. It gives off the ethmoidal nerves to the ethmoidal 
sinuses and the long ciliary nerves to the eye which carry sensory fibres 
from the cornea and sympathetic fibres to the dilator pupillae. All 
branches of the ophthalmic division are sensory. 

(b) The maxillary division (Fig. 57.2) 

This leaves the cranial cavity through the foramen rotundum and enters 
the pterygopalatine fossa . It has the sphenopalatine ganglion attached 
to it which transmits parasympathetic fibres to the lacrimal gland via 
communications with the lacrimal nerve. The branches of the maxillary 
nerve are the greater and lesser palatine nerves to the hard and soft 



palates, the sphenopalatine nerve to the nasal cavity and thence via the 
nasal septum, to the incisive fossa to supply the hard palate. The pos- 
terior superior dental nerve enters the back of the maxilla and supplies 
the teeth. The maxillary nerve leaves the sphenopalatine fossa via the 
inferior orbital fissure, travels in the floor of the orbit where it gives the 
middle and anterior superior dental nerves, and emerges onto the face 
through the infraorbital foramen as the infraorbital nerve. All branches 
of the maxillary division are sensory. 

(c) The mandibular division (Fig. 57.3) 

This leaves the cranial cavity through the foramen ovale and immedi- 
ately breaks up into branches. These are: the mainly sensory inferior 
alveolar nerve, which enters the mandibular foramen to supply the 
teeth before emerging onto the face as the mental nerve. This nerve 
does have one motor branch, the mylohyoid nerve, which supplies the 
mylohyoid and the anterior belly of the digastric. The lingual nerve lies 
close to the mandible just behind the third molar and then passes for- 
wards to supply the tongue. It is joined by the chorda tympani which 
carries taste fibres from the anterior two-thirds of the tongue and 
parasympathetic secretomotor fibres to the submandibular and sublin- 
gual salivary glands. These synapse in the submandibular ganglion 
which is attached to the lingual nerve. The auriculotemporal nerve sup- 
plies sensory fibres to the side of the scalp. It also carries parasympath- 
etic secretomotor fibres, which have synapsed in the otic ganglion, to 
the parotid gland. The buccal nerve carries sensory fibres from the face. 
There are muscular branches to the muscles of mastication, including 
the deep temporal nerves which supply temporalis. The mandibular 
division thus contains both motor and sensory branches. 



The trigeminal nerve (V) 1 29 



58 Cranial nerves VI-XII 




Greater pet rosa 
Temporal 

Zygomatic 
Buccal 



Marginal 
mandibular 

Cervical — 



Internal auditory meatus 
Facial nerve 

Middle ear 

Stylomastoid foramen 
Chorda tympani 



Fig.56.1 

The course of the facial nerve. 

The nerve passes through the middle ear and the parotid gland 



Spinal accessory 



Foramen 
magnum 



To sternomastoid 
and trapezius 



Internaljugular vein 




Cardiac branch 
Subclavian artery 

Fig.56.2 

The vagus and accessory nerves. 

The spinal rootof the accessory is shown in yellow 



Vagus 

Cranial accessory 

Internal carotid 

Cardiac branch 
External carotid 

Pharyngeal 

Superior laryngeal 
Internal laryngeal 

External laryngeal 
Cricothyroid 

Recurrent laryngeal (left) 



1 30 Head and neck 



• VI. The abducent nerve (see Fig. 56.3): leaves the brain at the pos- 
terior border of the pons and has a long intracranial course (so is often 
the first nerve to be affected in raised intracranial pressure) to the cav- 
ernous sinus, where it is closely applied to the internal carotid artery, 
and thence to the orbit via the superior orbital fissure. It supplies the lat- 
eral rectus. 

• VII. The facial nerve (Fig. 58.1): this leaves the brain near the cere- 
bellum and passes laterally into the internal auditory meatus. It reaches 
the medial wall of the middle ear and turns backwards and down- 
wards to leave the skull via the stylomastoid foramen. It then traverses 
the parotid gland, in which it divides into five branches {temporal, 
zygomatic, buccal, marginal mandibular and cervical) which are 
distributed to the muscles of facial expression, the platysma and the 
posterior belly of the digastric. In the middle ear it gives off the greater 
petrosal branch which carries parasympathetic fibres to the 
sphenopalatine ganglion and thence to the lacrimal gland. In the middle 
ear it also gives off the chorda tympani which joins the lingual nerve 
and is distributed with it. Sensory fibres in the chorda tympani have 
their cell bodies in the geniculate ganglion which lies on the facial 
nerve where it turns downwards. 

• VIII. The vestibulocochlear (auditory) nerve: this leaves the brain 
next to the facial nerve and enters the internal auditory meatus. It 
divides into vestibular and cochlear nerves. 

• IX. The glossopharyngeal nerve (see Fig. 65.1): leaves the brain at 
the side of the medulla and passes through the jugular foramen. It then 
curves forwards between the internal and external carotid arteries to 
enter the pharynx between the superior and middle constrictors. It sup- 
plies sensory fibres to the posterior one third of the tongue (including 
taste) and the pharynx. It also gives a branch to the carotid body and 
sinus. 

• X. The vagus nerve (Fig. 58.2): arises from the side of the medulla 
and passes through the jugular foramen. It is joined by the accessory 
nerve but the spinal root of the accessory leaves it again almost imme- 
diately. The cranial root is distributed with the vagus (hence the 
name— it is accessory to the vagus). The vagus carries two ganglia for 
the cell bodies of its sensory fibres. It descends between the internal 
carotid artery and the jugular vein, within the carotid sheath, and enters 



the thorax where its further course is described in Chapters 2 and 3. In 
the neck the vagus (and cranial root of the accessory) gives the follow- 
ing branches: 

• The pharyngeal branch which runs below and parallel to the glos- 
sopharyngeal nerve and supplies the striated muscle of the palate 
and pharynx. 

• Superior and inferior cardiac branches which descend into the 
thorax to take part in the cardiac plexuses. 

• The superior laryngeal nerve which divides into internal and exter- 
nal laryngeal nerves. The former enters the larynx by piercing the 
thyrohyoid membrane and is sensory to the larynx above the level of 
the vocal cords, and the latter is motor to the cricothyroid muscle. 

• The recurrent laryngeal nerve. On the right side it loops under the 
subclavian artery before ascending to the larynx behind the com- 
mon carotid artery. On the left side it arises from the vagus just 
below the arch of the aorta and ascends to the larynx in the groove 
between the trachea and oesophagus. The recurrent laryngeal 
nerves supply all the muscles of the larynx except for cricopharyn- 
geus and are sensory to the larynx below the vocal cords. 

• XI. The accessory nerve (Fig. 58.2): the cranial root arises from the 
side of the medulla with the vagus and is distributed with it. The spinal 
root arises from the side of the upper five segments of the spinal cord, 
enters the cranial cavity through the foramen magnum and joins the 
vagus. It leaves the vagus below the jugular foramen and passes back- 
wards to enter sternomastoid, which it supplies. It then crosses the pos- 
terior triangle to supply trapezius (see Fig. 61 .3). 

• XII. The hypoglossal nerve (Figs 59.1 and 65.1): arises from the 
side of the medulla ventral to the vagus and cranial accessory and 
passes through the hypoglossal canal. Below the skull it is joined by the 
anterior ramus of C 1 and it then runs downwards and forward, across 
the carotid sheath and the upward loop of the lingual artery to enter the 
tongue. It supplies the intrinsic and extrinsic muscles of the tongue. It 
gives off the descendens hypoglossi but this is actually composed of 
fibres from CI . This joins the descendens cervicalis, derived from C2 
and 3, to form the ansa cervicalis. From this, branches arise to supply 
the 'strap muscles', i.e. sternothyroid, sternohyoid, thyrohyoid and 
omohyoid. 



Cranial nerves VI-XII 131 



59 The arteries I 




Foramen spinosum 
Middle meningeal 



Facial 
Dorsal 
lingual 
Lingual 



Laryngeal branch 



Thyroid 
Thyrocervical trunk 



Superficial 
temporal 



Maxillary 
Occipital 
Tonsillar branch 
Hypoglossal nerve 
Internal carotid 
External carotid 
Carotid sinus 

Superior thyroid 

Recurrent laryngeal 

nerve 

Inferior thyroid 

Subclavian 



Fig.59.1 

The course and main branches of the external carotid artery. 
The inferior thyroid artery is also shown 




Fig.59.3 

Carotid angiogram showing internal carotid stenosis 



Anterior cerebral 



Anterior clinoid process 

Central artery 

of retina 

Ophthalmic 

artery 

Optic canal 




Abducent 
nerve 



Internal 
carotid 



Striate arteries 
Middle cerebral 
Posterior communicating 
Posterior cerebral 
Superior cerebellar 
Cavernous sinus 
Internal auditory 
Anterior inferior cerebellar 
Vertebral 

Posterior inferior cerebellar 

Anterior and posterior spinal 
Carotid canal 



Fig.59.2 

The intracranial course of the internal carotid artery. 

The intracranial partsof the two vertebral arteries are also shown diagrammatically 

although they are in a different plane 



132 Head and neck 



The common carotid artery 

Arises from the brachiocephalic artery on the right and from the arch of 
the aorta on the left (Chapter 4). Each common carotid passes up the 
neck in the carotid sheath (Fig. 61.1), along with the internal jugular 
vein and the vagus nerve. At the level of the upper border of the thyroid 
cartilage it divides into internal and external carotid arteries. There are 
no branches. 

The external carotid artery (Fig. 59. i) 

Ascends in the neck a little in front of the internal carotid to divide into 
its two terminal branches, the maxillary and superficial temporal arter- 
ies, in the substance of the parotid gland. 
Branches: 

• The superior thyroid artery: runs downwards on the side of the 
pharynx before passing forwards to the upper pole of the thyroid gland 
where it divides into two branches. The upper branch follows the upper 
border of the gland towards the isthmus and the lower passes down the 
posterior border to anastomose with the inferior thyroid artery. There 
are a number of branches to the larynx. 

• The lingual artery: arises at the level of the tip of the greater horn of 
the hyoid and loops upwards for a short distance before running for- 
ward deep to hyoglossus to enter and supply the tongue. It gives a num- 
ber of dorsal lingual arteries. The upward loop of the lingual is crossed 
by the hypoglossal nerve. 

• The facial artery: travels forwards, deep to the mandible where it is 
embedded in the back of the submandibular gland. It then curls round 
the lower border of the mandible to reach the face. Here it follows a tor- 
tuous course at the side of the mouth and lateral to the nose to reach the 
medial angle of the eye where it anastomoses with branches of the oph- 
thalmic artery. It gives off a tonsillar branch in the neck, superior and 
inferior labial branches and nasal branches. The facial arteries anasto- 
mose very freely across the midline and with other arteries on the face. 

• The occipital artery: passes backwards, medial to the mastoid pro- 
cess, and supplies the back of the scalp. 

• The superficial temporal artery: emerges from the parotid gland 
and runs up in front of the ear where its pulsations may be felt. It is dis- 
tributed to the side of the scalp and the forehead. 

• The maxillary artery: emerges from the parotid gland and passes 
deep to the neck of the mandible. It ends by entering the pterygopala- 
tine fossa through the pterygomaxillary fissure. Its principal branches 
are to the local muscles including the deep temporal arteries to tem- 
poralis and: 

• The inferior alveolar artery— crAcK the mandibular canal to supply 
the teeth. 



• The middle meningeal artery — runs upwards to pass through the 
foramen spinosum. Inside the skull it passes laterally and then 
ascends on the squamous temporal bone in a deep groove, which it 
shares with the corresponding vein. The anterior branch passes 
upwards and backwards towards the vertex and Ihe posterior branch 
passes backwards. It supplies the dura mater and the bones of the 
cranium. After head injuries it may bleed to produce a subdural 
haemorrhage , the symptoms of which may be delayed for some time 
after the injuiy. 

• Branches which accompany the branches of the maxillary nerve in 
the pterygopalatine fossa and have the same names. 

The internal carotid artery (Figs 59.2 and 59.3) 

At its origin from the common carotid artery it is enlarged to form the 
carotid sinus, a slight dilatation which has baroreceptors supplied by 
the glossopharyngeal nerve in its wall. Associated with this is the 
carotid body, a chemoreceptor supplied by the same nerve. The inter- 
nal carotid has no branches in the neck. It enters the cranial cavity via 
the carotid canal in the petrous temporal bone, accompanied by a sym- 
pathetic plexus. Within the skull it passes forwards in the cavernous 
sinus and then turns backwards behind the anterior clinoid process to 
break up into its three terminal branches. 
Branches: 

• The ophthalmic artery: enters the orbit through the superior orbital 
fissure and follows the nasociliary nerve. It gives the important central 
retinal artery which enters the optic nerve and supplies the retina. This 
is an end-artery so that occlusion causes immediate blindness. Other 
branches are described on p. 155. 

• The anterior cerebral artery: winds round the genu of the corpus 
callosum and supplies the front and medial surfaces of the cerebral 
hemisphere. It anastomoses with its fellow of the opposite side. 

• The middle cerebral artery: traverses the lateral sulcus on the lat- 
eral surface of the hemisphere and supplies the hemisphere (including 
the main motor and sensory areas) as well as giving the striate arteries 
which supply deep structures including the internal capsule. 

• The posterior communicating artery: a small artery which passes 
backwards to join the posterior cerebral artery, a terminal branch of 
the vertebral artery. 

These arteries and the communications between them form the 
Circle of Willis so that there is (usually) free communication between 
the branches of the two internal carotid arteries across the midline. 
There is, however, considerable variation in the arrangement of the 
circle. 



The arteries I 133 



60 The arteries II and the veins 



Scalenus anterior 



Dorsal scapular 
(usually) 

Axillary artery 
Subclavian artery 
First rib 



Internal thoracic artery 




C6 

Inferior 
thyroid artery 

Vertebral artery 

Thyrocervical 
trunk 

Costocervical 
trunk 




Subclavian artery 

Costocervical 
trunk 

First rib 

Superior 
intercostal artery 



Apex of lung 



Fig.60.1 

The branches of the subclavian artery 




EJeginning of superior 
sagittal sinus 

EJeginning of inferior 
sagittal sinus 

Superior ophthalmic vein 

Intercavernous sinuses 
Cavernous sinus 

Superior petrosal sinus 
Inferior petrosal sinus 
Jugular foramen 
Sigmoid sinus 

Transverse sinus 

Great cerebral vein 
Straight sinus 
Tentorium cerebelli 
Transverse sinus 




Posterior 

cerebral 

artery 



Posterior 

inferior 

cerebellar 

artery 

Vertebral 

artery 



Fig.60.2 

The intracranial venous sinuses 



Fig.60.3 

Vertebral angiogram 



1 34 Head and neck 



The subclavian artery (Figs 60.1 and 63. i) 

Arises from tlie brachiocephalic artery on the rigiit and tlie arch of the 
aorta on tlie left. It arches across the upper surface of the 1st rib to 
become the axillary artery. It is in close contact with the apex of the 
lung and lies behind scalenus anterior at the root of the neck. 
Branches: 

• The internal thoracic artery: seep. 13. 

• The vertebral artery: runs upwards to enter the foramen transver- 
sarium of the 6th cervical vertebra. It passes through corresponding 
foramina in the other cervical vertebra to reach the upper surface of the 
atlas. Here it turns medially in a groove and then enters the cranial cav- 
ity through Iheforamen magnum. Here it joins its fellow of the opposite 
side to form the basilar artery. It gives off the anterior and posterior 
spinal arteries which descend to supply the spinal cord, and \hc poster- 
ior inferior cerebellar artery which supplies not only the cerebellum 
but also the medulla. The basilar artery passes forwards on the under- 
surface of the medulla and pons and gives the anterior inferior cerebel- 
lar artery, branches to the brainstem and to the inner ear (the internal 
auditory artery) and ends by dividing into the superior cerebellar and 
posterior cerebral arteries. The latter is joined by th& posterior com- 
municating artery (p. 133). 

• The costocervical trunk: a small artery that passes backwards to 
supply muscles of the back. It also supplies the superior thoracic artery 
(see Chapter 3). 

• The thyrocervical trunk: gives off the superficial cervical and 
suprascapular arteries and then passes medially as the inferior thyroid 
artery across the vertebral artery to reach the middle of the posterior 
border of the thyroid. It has a variable relation to the recurrent laryngeal 
nerve, lying in front or behind them, but may branch early with the 
nerve passing between the branches. 

• The dorsal scapular artery: usually given off from the third part 
(Fig. 63.1). It descends along the medial border of the scapula but may 
arise in common with the superficial cervical artery. 

The veins 

The veins of the brain drain into dural venous sinuses (Fig. 60.2). The 
most important of these are: 

• The superior sagittal sinus: passes backwards in the midline in the 
attached border of the falx cerebri from just above the cribriform plate 
to the occipital region, where it communicates with the straight sinus, 
and then turns to the right to form the right transverse sinus. It then 
winds down on the back of the petrous temporal as the sigmoid sinus 



which passes through the right jugular foramen to form the right inter- 
nal jugidar vein. 

• The inferior sagittal sinus: begins near the origin of the superior 
sagittal sinus and runs in the free border of the falx cerebri. It is joined 
by the great cerebral vein to form the straight sinus which lies in the 
attachment of the falx to the tentorium cerebelli. The straight sinus 
turns to the left to form the left transverse sinus and then the sigmoid 
sinus. The latter leaves the skull through the left jugular foramen. 

• The cavernous sinus: this lies at the side of the pituitary fossa and 
contains the internal carotid artery. It receives the superior and inferior 
ophthalmic veins and is connected to some smaller sinuses — the super- 
ior and inferior petrosal sinuses and the .sphenoidal sinus. The two 
cavernous sinuses are joined in front and behind the pituitary by the 
intercavernous sinuses. 

• The emissary veins: seep. 123. 

• The internal jugular vein: passes down the neck from the jugular 
foramen, in the carotid sheath along with the internal and common 
carotid arteries and the vagus nerve. It ends by joining the subclavian 
vein to form the brachiocephalic vein. It receives veins corresponding 
to the branches of the external carotid artery {facial, lingual, pharyn- 
geal, and the superior and middle thyroid veins). The inferior thyroid 
veins pass downwards in front of the trachea to open into the left bra- 
chiocephalic vein. 

The facial vein communicates around the orbit with tributaries of the 
ophthalmic veins so that infections of the face may spread to the cav- 
ernous sinus if not properly treated. 

• The external jugular vein: begins in the parotid gland by the joining 
of the retromandibular vein with other small veins. It passes obliquely 
across sternomastoid to open into the subclavian vein. It receives the 
transverse cervical, suprascapular and anterior jugular veins near its 
lower end. 

• The anterior jugular vein: begins below the chin and runs down the 
neck near the midline. It then passes deep to sternomastoid to join the 
external jugular vein. 

• The subclavian vein: lies in a groove on the 1st rib but is separated 
from the subclavian artery by the scalenus anterior. It receives the 
external jugular vein, veins corresponding to the branches of the sub- 
clavian artery and, at its junction with the internal jugular vein, the thor- 
acic duct on the left and the right lymph duct on the right. 

• The vertebral vein: this is formed at the level of the 6th foramen 
transversarium from the vertebral plexus of veins that accompany the 
vertebral artery. 



The arteries II and the veins 1 35 



61 Anterior and posterior triangles 




Pretracheal fascia 
Investing layer of deep fascia 
Sternomastoid 
Common carotid artery 
Internaljugular vein 

Vagus nerve 
Prevertebral fascia 
Skin and superficial fascia 
Trapezius 



Fig.61.1 



The basic plan of the neck in cross-section. 
The arrows indicate the posterior triangle 



Pretracheal fascia 



Thyroid 



Thoracic duct 
Longus colli 
Long thoracic 
nerve 

Prevertebral 
fascia 



Greater auricular 

Lesser occipital 
Semispinalis — 
Splenius capitis 
Trapezius 




Left recurrent laryngeal nerve 

Trachea 

Sternomastoid 

Externaljugular 

Carotid sheath 

Vagus 

Sympathetic trunk 

Scalenus anterior 

Spinal nerve 

Plane of accessory 

nerve 

Scalenus medius 

Levator scapulae 

Splenius 

Trapezius 

Semispinalis — ^^^"^ A 

^ Vertebral artery 

Fig.61.2 

A more detailed plan of the neck, based on Fig. 61.1. 
There are still some structures omitted from the diagram 
for the sake of simplicity, for example the strap muscles 




Levator scapulae 
Accessory nerve 

Scalenus medius 

Brachial plexus 
(upper trunk) 

Scalenus anterior 

Fig.61.3 

The main structures in the posterior triangle 



Parotid 

Externaljugular 
vein 

Transverse 

cutaneous 

Supraclavicular 

nerves 

Anteriorjugular 

vein 

Omohyoid 



Anterior belly of digastric 
Digastric triangle 

Posterior belly of digastric 



Submental 

triangle 

Omohyoid 

Muscular 

triangle 




Fig.61.4 

Subdivisions of the anterior triangle 



Hyoid bone 

Carotid 

triangle 



Sternocleidomastoid 



1 36 Head and neck 



The neck consists essentially of five blocks of tissue running longitudin- 
ally (Figs 61.1 and 61.2). These are as follows: 

1 The cervical vertebrae surrounded by a number of muscles and 
enclosed in a dense layer of prevertebral fascia. 

2 The pharynx and larynx, partially enclosed in a thin layer of pre - 
tracheal fascia. Below the level of C6 these give way to the oesophagus 
and trachea. 

3 & 4 Two vascular packets consisting of the common and internal 
carotid arteries, the internal jugular vein and the vagus nerve, all 
enclosed in the fascial carotid sheath. 

5 An outer enclosing sheath consisting of the sternomastoid and 
trapezius and the investing layer of deep fascia of the neck. 

The anteriortriangle 

The anterior triangle (Fig. 61 .4) is bounded by: 

• The lower border of the mandible and its backward continuation. 

• The anterior border of sternomastoid. 

• The midline of the neck. 

The anterior triangle is subdivided into: 

(a) The digastric triangle, bounded by: 

• The lower border of the mandible. 

• The two bellies of the digastric. 

(b) The carotid triangle, bounded by: 

• Thesuperiorbelly of the omohyoid. 

• The posterior belly of the digastric. 

• The anterior border of sternomastoid. 

(c) The muscular triangle, bounded by: 

• The superior belly of the omohyoid. 

• The anterior border of sternomastoid. 

• The midline of the neck. 



The contents of these triangles are mostly structures that are continu- 
ous, without interruption, from one triangle to another so that it is more 
convenient to describe them individually in other chapters. 

The posterior triangle (Fig. 6i.3) 

The posterior triangle is bounded by: 

• The posterior border of sternomastoid. 

• The anterior border of trapezius. 

• The middle part of the clavicle. 

Stretching between the two muscles is the investing layer of deep 
fascia which splits to enclose them and continues to the anterior tri- 
angle. Embedded in the deep fascia is the spinal part of the accessory 
nerve which leaves the sternomastoid about halfway down its posterior 
border and passes into trapezius two flngerbreadths above the clavicle. 
It supplies both muscles. Four cutaneous nerves {transverse cervical, 
supraclavicular, greater auricular and lesser occipital) also emerge 
near the accessory nerve and supply the skin of the neck and the upper 
part of the chest. The external jugular vein begins near the upper end of 
sternomastoid and runs down obliquely across this muscle to enter the 
subclavian vein. It is joined by the anterior jugular and other small 
veins at its lower end. The inferior belly of the omohyoid muscle 
crosses the lower part of the triangle. 

The floor of the posterior triangle is the prevertebral fascia, deep 
to which lie, from below upwards: scalenus anterior, scalenus medius 
and posterior, levator scapulae, and splenius capitis. 

Structures deep to the prevertebral fascia 

• The upper, middle and lower trunks of the brachial plexus which 
emerge between the scalenus anterior and the scalenus medius, the 
lower trunk resting on the 1st rib. 

• The supraclavicular branches of the brachial plexus (p. 73). 



Anterior and posterior triangles 1 37 



62 The pharynx and larynx 



Superior constrictor 
Buccinator 



Pterygomandibular 
ligament 

Stylopharyngeus 

Stylohyoid ligament 



Attachment of 
thyrohyoid 
Attachment of 
sternohyoid 
Inferior constrictor 
Cricothyroid 



Cricoid cartilage 



Oesophagus 




Nerves 

Glossopharyngeal 



Superior laryngeal 
Internal laryngeal 
External laryngeal 



Recurrent laryngeal 



Fig.62.1 

The pharynx and larynx, and some of the related nerves 



Epiglottis 



Cricothyroid 

Position of 
synovialjoint 




Vocal process 



Arytenoid 
Muscular 
process 
Crico 



arytenoid 
joint 

Facet for 
inferior horn 
of thyroid 




Epiglottis 

Thyroid 
cartilage 

Vocal 
ligament 

Cricovocal 
membrane 

Cricoid 

First ring 
of trachea 



Fig.62.2 

A midline section of the larynx to show the 
cricowcal membrane and vocal ligaments 



Greater horn of hyoid 

Epiglottis 

Ala of thyroid cartilage 

Arytenoid 

Muscular process 
Crico-arytenoid muscle 
(posterior) 
Cricoid 




Fig.62.3 

Left, the cricothyroid muscle and right, the posterior crico-arytenoid 




Vocal ligament 

Thyro-arytenoid 
muscle 

Vocal process 

Lateral 

crico-arytenoid 
Posteror 




crico-arytenoid 
Fig.62.4 

The muscles causing abduction, adduction and relaxation 

of the vocal cords. Tightening of the cords is shown in Fig.62.3 



Base of tongue 
Vallecula 




Trachea 



Glossoepiglottic 
fold 

Epiglottis 
Epiglottic 
tubercle 
Vocal fold 
Vestibular fold 

Aryepiglottic 
fold 



Fig.62.5 

The larynx as seen through a laryngoscope 



138 Head and neck 



The pharynx 

This is an incomplete striated muscular tube, opening in front into tiie 
nasal cavity, the mouth and the larynx, thus being made up of the 
nasopharynx, the oropharynx and the laryngopharynx. The muscular 
coat (Fig. 62.1) is formed by: 

• The superior constrictor: arises from the pterygomandibular liga- 
ment (which spans between the pterygoid hamulus and the mandible 
just behind the third molar tooth). 

• The middle constrictor: arises from the stylohyoid ligament and the 
lesser and greater horns of the hyoid bone. 

• The inferior constrictor: arises from the thyroid and cricoid 
cartilages. 

The constrictors encircle the pharynx and interdigitate posteriorly. 
The gaps between the constrictors are filled in by fascia. There is also 
an inner longitudinal layer of muscle. The nasopharynx is lined by cili- 
ated columnar epithelium and on its posterior wall is situated a mass of 
lymphatic tissue, the pharyngeal tonsil or adenoid. The pharyngotym- 
panic (Eustachian) tube opens into the nasopharynx at the level of the 
floor of the nose, the cartilage of the tube producing a distinct bulge 
behind the opening. 

• Nerve supply: 

• Motor — pharyngealbranchof the vagus (p. 131). 

• Sensory — glossopharyngeal (p. 131). 

The larynx 

Palpable components 

• Hyoid bone, level of C3. 

• Thyroid cartilage, level of C4 and 5. 

• Cricoid cartilage, level of C6. 

Other components 

• Arytenoid cartilages: attached to upper border of the cricoid by syn- 
ovial joints so that they can slide and rotate. Each has an anterior vocal 
process and a lateral muscular process (Figs 62.2 and 62.3). 

• Epiglottis: a leaf-shaped piece of elastic cartilage attached to the 
back of the thyroid cartilage (Fig. 62.2) and projecting upwards behind 
the hyoid. 

• Thyrohyoid ligament: joins the hyoid and the thyroid (Fig. 62.1). 

• Crico vocal membrane (cricothyroid ligament): attached to the 
upper border of the cricoid and passes inside the thyroid to be attached 
to the back of the thyroid and to the vocal processes of the arytenoids 
(Fig. 62.2). The upper border is thickened to form the vocal ligament 
which, with the mucous membrane that covers it, forms the vocal 
cords. 

• Cricothyroid joint: a small synovial joint between the inferior horn 
of the thyroid cartilage and the cricoid, permitting a hinge-like move- 
ment (Fig. 62.3). 



• Pyriform fossa: the fossa between the posterior border of the thyroid 
cartilage and the cricoid and arytenoid cartilages. It is important he- 
cause a carcinoma in this region can remain 'silent' until it has spread 
to the cei'vical lymph nodes whereas a tumour of the vocal cords pro- 
duces early voice changes. 

• Mucous membrane: mostly respiratory epithelium (ciliated colum- 
nar) but over the vocal cords it changes to stratified squamous so that 
the cords have a pearly appearance (Fig. 62.5). 

• Vestibular folds: a pair of additional folds above the vocal folds 
[false cords). The space between the vocal and vestibular folds is the 
sinus of the larynx. 

The intrinsic muscles of the larynx 

• Cricothyroid (Figs 62.1 and 62.3): situated on the outside of the 
larynx. Tenses the vocal cords. 

• Thyroarytenoid (Fig. 62.4): from the back of the thyroid cartilage to 
the vocal process of the arytenoid. Relaxes the vocal cords. 

• Posterior cricoarytenoid (Figs 62.3 and 62.4): from the back of the 
cricoid to the muscular process of the arytenoid. Abducts the vocal 
cords. 

• Lateral cricoarytenoid (Fig. 62.4): adducts the vocal cords. 

• Interarytenoids and aryepiglottic muscle: form a 'sphincter', to- 
gether with the epiglottis, in order to close off the entrance to the larynx 
(glottis) during swallowing. 

• Nerve supply: 

• Motor — recurrent laryngeal nerve, except for the cricothyroid 
which is supplied by the external laryngeal nerve. 

• Sensory — above the vocal cords, the internal laryngeal nerve 
which enters the larynx through the thyrohyoid membrane. Below 
the vocal cords, the recurrent laryngeal nerve (which is therefore a 
mixed nerve) which enters the larynx just behind the cricothyroid 
joint. 

Laryngoscopy (Fig. 62.5) 

The vocal cords may be seen by means of a warmed, angled mirror 
passed to the back of the throat. Only the edges of the cords can be seen 
because of the shadow of the false cords. Adduction of the cords may be 
obser^'ed by asking the patient to say a high-pitched 'eeeee' while 
abduction occurs when saying 'Ahhh' . If one of the recurrent laryngeal 
nerves is divided, the cord lies in a position midway between adduction 
and abduction but this does not produce very severe voice changes 
because the uninjured cord can cross the midline to reach the para- 
lysed cord. However, if both nerves are cut the cords lie in the cadaveric 
position, i.e. in the mid-position. If both nerves are damaged but not 
completely divided the cords are adducted since the abductors are 
more affected than the adductors (Semon's law). This may cause 
breathing difficulties. 



The pharynx and larynx 139 



63 The root of the neck 



Middle cervical ganglion 
Scalenus medius 



Scalenus anterior 
Phrenic nerve 



Uppertrunkof brachial plexus 

Superficial cervical artery 

Suprascapular artery, nerve - 
Dorsal scapular artery 



Internal thoracic artery 




Vertebral artery 
Sympathetic trunk 

Inferior thyroid artery 



Vagus 

Subclavian artery 
Subclavian vein 
Carotid sheath 
Inferior cervical ganglion 



Thoracic duct 



Fig.63.1 

The deep structures at the root of the neck and in the thoracic outlet. 

The curved arrow on the right side of the diagram indicatesthecourseof the thoracic duct 



Scalenus posterior 

Attachment of scalenus medius 

Serratus anterior 

(first digitation) 

Lower trunk of brachial plexus 

Subclavian artery 

Subclavian vein 




Sympathetic trunk 
Superior intercostal artery 
1st thoracic nerve 
8th cervical nerve 

Scalene tubercle, 
for attachment of 
scalenus anterior 



Subclavius 

Fi/!i B"? 2 Costoclavicular ligament 

The structures related to the upper surface of the first rib 



The area defined by the first thoracic vertebra, the first ribs and the 
manubrium sterni is called the thoracic inlet (or outlet) (Fig. 63.1). 
Through this relatively confined space pass the trachea and oesopha- 
gus, the carotid and subclavian arteries and the corresponding large 
veins as well as the apices of the lungs and important nerves. 

The scalene muscles 

• Scalenus anterior: passes down from the transverse processes of 
some of the cervical vertebrae and is inserted by means of a narrow ten- 
don into the scalene tubercle on the medial border of the 1 st rib. 



• Scalenus medius: is behind scalenus anterior and is inserted by mus- 
cular fibres into a large area of the 1st rib. The subclavian artery and the 
trunks of the brachial plexus are between the two muscles and the sub- 
clavian vein is in front of scalenus anterior. The gap between the two 
muscles may be narrow and the tough tendon of scalenus anterior may 
compress the lower trunk of the brachial plexus and I or the subclavian 
artery, giving rise to one form of the thoracic outlet syndrome (see also 
cervical rib, p. 7). 



140 Head and neck 



The arteries 

• The subclavian artery (p. 135): on the right side, from the brachio- 
cephalic artery and, on the left, directly from the arch of the aorta. It 
arches over the apex of the lung and crosses the 1 st rib in a shallow 
groove, which it shares with the lower trunk of the brachial plexus 
(Fig. 63.2). At the outer border of the 1st rib it becomes the axillary 
artery. It has five branches (p. 135): 

• The vertebral artery. 

• The internal thoracic artery. 

• The thyrocervical trunk. 

• The costocervical trunk. 

• The dorsal scapular artery. 

The veins 

• The subclavian vein : begins at the outer border of the 1 st rib and lies 
in a shallow groove on the upper surface of the rib in front of scalenus 
anterior. At the medial border of this muscle it is joined by the internal 
jugularvein to form \he. brachiocephalic vein. The internal jugular vein 
is enclosed in the carotid sheath, along with the common carotid artery 
and the vagus nerve. Other veins entering it accompany the small arter- 
ies but the inferior thyroid veins are solitary and run down from the 
lower border of the thyroid gland, in front of the trachea, to reach the 
left brachiocephalic vein in the thorax. 



into the axilla. The suprascapular nerve arises from the upper trunk and 
joins the corresponding artery before passing back to the suprascapular 
notch. For further details, see Chapter 30. 

• The phrenic nerve: is formed by branches from the 3rd, 4th and 5th 
(mainly the 4th) cervical nerves and descends on the anterior surface of 
scalenus anterior before crossing the subclavian artery and entering the 
thorax. 

• The vagus nerve: this crosses the subclavian artery and descends 
into the thorax. On the right side it gives off the right recurrent laryn- 
geal nerve which hooks under the artery and ascends, deep to the com- 
mon carotid, to reach the larynx. The left recurrent laryngeal, having 
arisen in the thorax, runs upwards between the trachea and oesophagus. 

• The sympathetic trunlc descends close to the vertebral artery. The 
middle cervical ganglion is close to the entry of the artery into the fora- 
men transversarium of C6 and the inferior cervical ganglion is near the 
neck of the 1st rib behind the origin of the vertebral artery. It may be 
fused with the 1st thoracic ganglion to form the stellate ganglion. 

The thoracic duct (Fig. 63. i) 

On the left side only. The duct ascends out of the thorax between the 
trachea and oesophagus and arches laterally between the carotid sheath 
in front and the vertebral artery behind. It ends by joining the junction 
between the internal jugular and subclavian veins. 



The nerves 

• The upper, middle and lower trunks of the brachial plexus: 

emerge from between the scalenus anterior and medius and pass down 



The root of the neck 141 



64 The oesophagus and trachea and the thyroid gland 



Inferior thyroid 
artery 

Kiqht recurrent 
laryngeal nerve 




Thyrohyoid 

Superior thyroid artery 

Sternothyroid 

Cricothyroid 

Common carotid artery 

Inferior thyroid artery 
Inferior thyroid veins 
Left brachiocephalic vein 



Fig.64.1 

The thyroid and its blood supply. A large part of the right lobe has been removed 



The oesophagus 

The oesophagus begins at the level of the cricoid cartilage and runs 
down behind and slightly to the left of the trachea. The left recurrent 
laryngeal nerve is in the groove between the oesophagus and trachea 
and the thoracic duct is to the left of the oesophagus. 

The trachea 

The trachea begins at the level of the cricoid cartilage and ends by 
dividing into left and right bronchi at the level of the manubriosternal 
joint. The trachea can be palpated in the midline just above the sup- 
rasternal notch and can be seen in an X-ray as a dark shadow. The upper 
part of the trachea is crossed by the isthmus of the thyroid. The trachea, 
bronchi and lungs develop from a groove in the floor of the embryonic 
pharynx which normally separates off except at the upper end. Anomal- 
ies of the separation process are not uncommon (tracheo-oesophageal 
fistula), the commonest variety (85%) being that in which the upper 
segment of the oesophagus ends blindly while the upper end of the lower 
segment communicates with the trachea. 

The infrahyoid ('strap') muscles 

• sternothyroid: arises from the back of the manubrium and ascends 
to be attached to the outer surface of the thyroid cartilage. 

• Thyrohyoid: is a continuation of the latter and is attached to the 
hyoid bone. 

• Sternohyoid: is superficial to the other two and runs from the 
manubrium to the lower border of the hyoid. 

• Omohyoid: the superior belly is attached to the hyoid and runs down 
to its intermediate tendon and then continues as the inferior belly across 
the posterior triangle to be attached to the scapula. 



These infrahyoid muscles are all supplied by the ansa cervicalis (CI, 
2 and 3). Their function is to fix the hyoid bone so that the suprahyoid 
muscles have a fixed base. Their main importance lies in their close 
relation to the thyroid gland. 

The thyroid gland 

The thyroid is an endocrine gland with an extremely rich blood supply 
(Fig. 64.1). Its isthmus lies across the 3rd, 4th and 5th rings of the tra- 
chea and the lobes lie on either side, reaching up as far as the 'pocket' 
under the attachment of sternothyroid to the thyroid cartilage. It is 
enclosed in the thin pretracheal fascia and also has its own fibrous 
capsule. When the gland is enlarged, the strap muscles are stretched 
tightly over it and the carotid sheath is displaced laterally. An important 
diagnostic feature is that swellings of the thyroid move on swallowing. 

• Blood supply: 

• The superior thyroid artery — comes from the external carotid and 
runs down to enter the 'pocket' between the sternothyroid and the 
thyroid cartilage where it is close to the external laryngeal nerve. It 
divides into two branches which run down the posterior border and 
along the upper border. 

• The inferior thyroid artery— has been described above (p. 135) 
and there is a very free anastomosis between the two arteries and 
between their branches and the small arteries of the trachea and 
oesophagus. It is thus possible to tie all four arteries during subtotal 
thyroidectomy and still leave an adequate blood supply to the 
remaining thyroid tissue and the parathyroids. 

• Venous drainage: there are three veins on each side: the superior 
and middle thyroid veins drain into the internal jugular and the inferior 
into the left brachiocephalic. 



142 Head and neck 



Developmental anomalies 

The thyroid develops as an outgrowth from the floor of the pharynx 
(thyroglossal duct) in the position of the future foramen caecum of the 
tongue. It descends ventral to the larynx before dividing into two lobes. 
The stem of the outgrowth, the thyroglossal duct, normally disappears 
although it may remain in part. Aberrant thyroid tissue may occur any- 
where along the course of the duct or thyroglossal cysts may appear. 
Such thyroid remnants move upwards when the tongue is protritded. 
Infection of a persistent thyroglossal duct may occur, when the duct 
must be excised. 



The parathyroid glands 

There are two parathyroids, superior and inferior, on each side. They 
are about the size of a pea and are embedded in the baclc of the thyroid 
(but outside its capsule). They develop from the third (inferior parathy- 
roid) and fourth (superior parathyroid) pharyngeal pouches of the 
embryo. The thymus also develops from the third pouch and may drag 
the inferior gland down with it so that the adidt gland may lie in the 
thorax. 



The oesophagus and trachea and the thyroid gland 143 



65 The upper part of the neck and the submandibular region 



Internal carotid artery 

Glossopharyngeal nerve 

Superior laryngeal nerve 

Hypoglossal nerve 

Lingual artery 



Internal laryngeal nerve 
External laryngeal nerve 



Superior ramus of 
ansa cervicalis 




Hypoglossal nerve 
Internaljugular vein 
Occipital artery 

Spinal accessory nerve 

Vagus nerve 

C2 

C3 



Fig.65.1 

The last four cranial nerves and their relation to the large vessels 



Lingual branch 
ofV 

Stylohyoid and 
styloglossus 

XII 



Submandibular duct 
Lingual artery 




Disc 

Head of 
mandible 
Lateral 
pterygoid 

Styloid — 
process 

Fig.65.2 

The tempo romandibularjoint 




Hyoid 

Fig.65.3 

The extrinsic muscle of the tongue and the related nerves 



Sublingual gland 

Genioglossus 

Hyoglossus 

Geniohyoid 



Fibrocartilage 

External 
auditory 
meatus 



Mastoid 
process 



144 Head and neck 



The 'foundation' for the upper part of the neck consists of the superior 
and middle constrictors of the pharynx and on these lie the internal and 
external carotid arteries, the internal jugular vein and the last four cra- 
nial nerves (Fig. 65.1). 

• The glossopharyngeal runs forwards, across the internal carotid 
artery but deep to the external carotid (p. 131). 

• The vagus, which is joined by the cranial root of the accessory, runs 
straight down, between the internal carotid and the internal jugular and 
within the carotid sheath (p. 131). 

• The spinal root of the accessory runs backwards, crossing the inter- 
nal jugular vein and the transverse process of the atlas to supply ster- 
nomastoid and trapezius (p. 131). 

• The hypoglossal, having left the cranial cavity by means of the 
hypoglossal canal, is joined by the anterior ramus of the 1st cervical 
nerve, winds round the vagus and then runs downwards and forwards, 
superficial to both carotids, giving off the descendens hypoglossi in the 
process. The branches and distribution of these nerves have already 
been described (p. 131). 

The infratemporal region 

This is the region deep to the ramus of the mandible. 

Contents 

• The stem of the mandibular division of the trigeminal nerve 

which enters through the foramen ovale and immediately breaks up 
into branches (Chapter 57). 

• The otic ganglion, which lies medial to the nerve (Chapter 57). 

• The medial and lateral pterygoid muscles: the medial pterygoid is 
inserted into the inner surface of the ramus and thus separates the 
region from the structures lying on the superior constrictor, described 
above. The lateral pterygoid runs backwards from the lateral pterygoid 
plate to the neck of the mandible and the intra-articular disc. 

• The maxillary artery: enters the region by passing forwards deep to 
the neck of the mandible, and its branches correspond to those of the 
nerve with the addition of the middle meningeal artery which ascends 
to pass through the foramen spinosum. The maxillary artery leaves by 
entering the pterygopalatine fossa . 

• The temporomandibular joint (Fig. 65.2): this is a synovial joint 
with an intra-articular disc but, unlike most other synovial joints, the 
articular cartilage and the disc are composed of fibrocartilage or even 
fibrous tissue. The lateral pterygoid muscle can pull the disc and the 
head of the mandible forwards onto the articular eminence. This occurs 
when the mouth is opened so that the joint is not a simple hinge joint. 
The axis of rotation is through the mandibular foramen so that the in- 
ferior alveolar nerve and vessels are not stretched when the mouth is 
opened. The mouth is opened by gravity and the suprahyoid muscles 
such as mylohyoid and geniohyoid and closed by the masseter, tem- 
poralis and medial pterygoid. When the mouth is open and the head of 
the mandible is on the articular eminence the joint is unstable so that a 
blow on the chin may cause dislocation. 



Tlie submandibular region 

This is the region below the mandible and extending upwards deep to 
the mandible as far as the attachment of the mylohyoid muscle to the 
mylohyoid line of the mandible. The contents of the submandibular 
region include: 

Muscles 

• Mylohyoid: from the hyoid to the mylohyoid line on the mand- 
ible (Fig. 55.2). On its surface lies the anterior belly of the digastric 
muscle, and the two have the same nerve supply (the mylohyoid nerve). 

• The posterior belly of the digastric runs back to a groove medial to 
the mastoid process and the intermediate tendon is attached to the hyoid 
bone. 

• Hyoglossus: from the greater horn of the hyoid up to the side of the 
tongue. Is partly deep to mylohyoid. 

• The middle constrictor of the pharynx: behind and partly deep to 
the hyoglossus. 

Nerves and vessels (Fig. 65.3) 

• The lingual artery: leaves the external carotid with an upward loop 
and then runs forwards deep to the hyoglossus. It supplies the tongue. 

• The lingual nerve: enters the region by passing just behind the third 
molar tooth, directly in contact with the mandible, and then loops for- 
wards on the hyoglossus to enter the tongue. Suspended from it is the 
submandibular ganglion, in which parasympathetic fibres from the 
chorda tympani synapse before supplying the submandibular and sub- 
lingual glands. The lingual nerve carries sensory fibres from the anter- 
ior two-thirds of the tongue as well as taste fibres which are carried in 
the chorda tympani. 

• The hypoglossal nerve: crosses the loop of the lingual artery and 
then runs forwards on the hyoglossus, below the lingual nerve, to enter 
the tongue and supply its intrinsic and extrinsic muscles. 

Salivary glands 

• The submandibular gland: lies on the mylohyoid and the anterior 
belly of the digastric, extending up as far as the mylohyoid line. It also 
extends back onto the hyoglossus and has a deep process which passes 
forwards, deep to the mylohyoid. From this the submandibular 
(Wharton's) duct travels forwards to enter the mouth at the sublingual 
papilla near the midline. The duct is crossed by the lingual nerve which 
then passes deep to the nerve to enter the tongue. The facial artery is 
embedded in the posterior part of the gland before turning down, 
between the gland and the mandible, and then passing over the lower 
border of the mandible to supply the face. 

• The sublingual gland: lies deep to the mylohyoid near to the mid- 
line. Its upper surface is covered by the mucous membrane of the 
mouth and its numerous ducts open onto a ridge in the floor of the 
mouth extending back from the sublingual papilla. 



The upper part of the neck and the submandibular region 145 



66 The mouth, palate and nose 




Fig.66.1 

The upper surface of the tongue 



Fungiform papillae 
Filiform papillae 



Vallate papillae 



Foramen caecum 
Palatoglossal fold 

Lingual lymphatic 
tissue ('Lingual tonsil') 



Frontal sinus 



Opening of 
frontal sinus 



Openings of 
ethmoidal sini. 



Bulla ethmoidalis 
Hiatus 




semilunaris 
Inferior concha 



Fig.66.2 

The lateral wall of the nasal cavity 



Opening of 
maxillary sinus 



Opening of 
sphenoidal sinus 

Cut superior and 
middle conchae 

Adenoid 
Tubal elevation 

-Opening of 
auditory tube 



The hard palate is formed by \he. palatal process of the maxilla and the 
horizontal plate of the palatine bone. The soft palate hangs Uke a cur- 
tain behind the mouth cavity. 

Muscles 

• Levator palati: elevates the palate. 

• Tensor palati: tenses the palate. These two muscles move the soft 
palate so that it moves towards the back wall of the oropharynx where 
it meets a part of the superior constrictor which contracts strongly 
to form a ridge— the ridge of Passavant. The mouth and nasal cavi- 
ties are thus separated so that food does not regurgitate into the nose 
and so as to be able to pronounce the palatal consonants such as 'g' 
and 'k'. 

• Palatoglossus and palatopharyngeus: these pass downwards from 
the palate to the side of the tongue and the inside of the pharynx, respect- 
ively. They raise two ridges, the palatoglossal and palatopharyngeal 
arches, that are also called the anterior and posterior pillars of the 



fauces. They separate the mouth from the oropharynx and between 
them is the tonsillar fossa. 

The nerve supply of the pharynx 

The. pharyngeal plexus is a plexus of nerves formed by: 

• The pharyngeal hranch of the vagus, which includes the cranial 
root of the accessory. This provides the motor supply to the muscles 
except for the tensor palati which is supplied by the mandibular divi- 
sion of the trigeminal. 

• The glossopharyngeal nerve, which provides the sensory supply to 
the pharynx. 

• Branches from the sympathetic trunk. 

The nerve supply of the palate 

The palate is supplied by the greater and lesser palatine and the 
nasopalatine nerves from the maxillary division of the trigeminal 
(Fig. 57.2). These nerves also supply the inner surface of the gums. 



146 Head and neck 



other features 

• The tonsil: a mass of lymphatic tissue lying in the tonsillar fossa 
which, like the rest of the lymphatic system, reaches its maximum size 
at puberty. Lateral to the tonsil is its fibrous capsule and the superior 
constrictor. It is supplied by the tonsillar branch of the facial artery 
but the bleeding that occurs after tonsillectomy is usually from the 
paratonsillar vein. The pharyngeal tonsil (adenoid) has already 
been mentioned and there is also a lingual tonsil lying in the back of 
the tongue. 

• The teeth: the deciduous (milk) teeth comprise two incisors, a 
canine and two molars; the last occupy the position of the two pre- 
molars of the permanent teeth. The permanent teeth comprise two 
incisors, a canine, two premolars and three molars. The first milk teeth 
to erupt are usually the lower central incisors at about 6 months and the 
first permanent teeth are the first molars at about 6 years. 

The tongue 

The tongue is divided developmentally and anatomically into an an- 
terior two-thirds and a posterior one third, separated by the sulcus 
terminalis, a V-shaped groove with the foramen caecum at the apex 
(Fig. 66.1). The latter is the site of outgrowth of the thyroglossal duct. 
In front of the sulcus is a row of vallate papillae. Filiform papillae and 
red, flat-topped fungiform papillae can be seen on the more anterior 
parts of the tongue. 

Muscles (Fig. 65.3) 

• Intrinsic muscles: run in three directions, longitudinally, trans- 
versely and vertically. 

• Hyoglossus: from the greater horn of the hyoid bone. 

• Genioglossus: from the genial tubercle on the back of the mandible. 

• Styloglossus: from the styloid process. 

The latter three muscles blend in with the intrinsic muscles. 
Genioglossus is especially important as it is inserted along the whole 
length of the tongue so that it is used to protrude the tongue. 



in the chorda tympani. Posterior one third by the glossopharyngeal 
nerve. A small part of the tongue near the epiglottis is supplied by the 
internal laryngeal branch of the vagus nerve. 

Since the anterior part of the tongue develops from a pair of lingual 
swellings, the nerves and blood vessels of each side of the tongue do not 
cross the midline (although some lymphatics do) so that a midline inci- 
sion will not do any serious damage. If the motor supply is cut off on 
one side, the tongue will diverge to the affected side when protruded 
owing to the action of genioglossus on the sound side. 

The nasal cavity 

The boundaries of the nasal cavity include the: 

• Nasal septum: perpendicular plate of the ethmoid, vomer and a large 
plate of cartilage. 

• Lateral wall (Fig. 66.2): maxilla, lacrimal, ethmoid with its superior 
and middle conchae, perpendicular plate of the palatine, inferior con- 
cha (a separate bone). 

• Roof: nasal bones, cribriform plate of the ethmoid, body of the 
sphenoid. 

• Floor: palatal processes of the maxiUa and palatine bones. 

The spaces beneath the conchae are the meatuses and the region 
above the superior meatus is the spheno-ethmoidal recess. 

The paranasal sinuses 

• The maxillary sinus: inside the body of the maxilla, it opens into the 
middle meatus. Since the opening is in the upper part of the sinus it does 
not drain easily. 

• The frontal sinuses: on each side of the midline, just above the 
medial part of the orbit. They drain into the middle meatus. 

• The ethmoidal sinuses: in the body of the ethmoid bone and there- 
fore deep to the medial wall of the orbit. Drain into the middle and 
superior meatuses. 

• The sphenoidal sinus: inside the body of the sphenoid. Drains into 
the spheno-ethmoidal recess. 



Nerve supply 

• Motor: hypoglossal nerve. 

• Sensory: anterior two-thirds by the lingual nerve; taste fibres travel 



The nasolacrimal duct 

Drains tears from the medial angle of the eye. Drains into the inferior 
meatus. 



The mouth, palate and nose 147 



67 The face and scalp 



Frontal belly of occipitofrontalis 

Temporalis 

Orbicularis oculi 

Zygomaticus major 

Zygomaticus minor 

Levator labii superioris (elevator of the upper lip) 

Buccinator 

Levator anguli oris (elevator of the angle of the mouth) 

Orbicularis oris 

Outline of parotid (salivary) gland 

Masseter 

Depressor anguli oris (depressorof the angle of the mouth) 

Depressor labii inferioris (depressor of the lower lip) 

Fig.67.1 Platysma 

The principal muscles of facial expression and two of the musclesof mastication, temporalis and masseter 




The facial muscles 

• Muscles of mastication: see Muscle index, p. 167. They are all sup- 
plied by the mandibular division of the trigeminal (p. 1 29). 

• Muscles of facial expression: they are all supplied by the facial 
nerve. They have only one attachment to bone, or sometimes no attach- 
ment at all, the other end of the muscle being inserted into skin or 
blending with other muscles. The most important are shown in Fig. 



67.1, from which their actions can be deduced. The orbicularis oculi 
has an orbital part which surrounds the eye as a sphincter and closes the 
eye tightly, while the palpebral part, which is in the eyelid, closes the 
eye gently as in sleep. The most important function of the buccinator is 
to keep the cheeks in contact with the gums so that food does not collect 
in this region. The platysma extends down the neck and over the clavi- 
cle and upper part of the chest. 



148 Head and neck 



Facial nerve 
Parotid 



Sternocleidomastoid 

Mastoid process 

Posterior belly of digastric 
Carotid sheath 




Fig.67.2 

A horizontal section through the parotid to show its relations 



Masseter 
Parotid duct 

Mandible 

Medial pterygoid 

Retromandibular vein 

Maxillary artery 

Wall of pharynx 

External carotid artery 

Styloid process and 3 'stylo-' muscles 



The parotid gland 

Situated mainly beiiind tlie mandible but spills over it onto the face. It 
extends deeply to come into contact with the pharynx and posteriorly it 
is moulded around the mastoid process and sternomastoid. The parotid 
duct extends forwards across masseter to enter the mouth opposite 
the second upper molar. The whole gland is enclosed in dense fascia so 
that swelling of the gland, as in mumps for instance, is very painful. 
Three structures pass through the gland (Fig. 67.2). These are, from 
superficial to deep: the facial nerve, the retromandibular vein (the 
beginning of the external jugular) and the external carotid artery, with 
its maxillary and superficial temporal branches. 



Nerves of the face 

• The facial nerve: having left the stylomastoid foramen, the facial 
nerve enters the parotid and divides into frontal, zygomatic, buccal, 
marginal mandibular and cervical branches (Fig. 67.3), with some 
intercommunicating branches between them. Note that the marginal 
mandibular branch lies below the mandible for part of its course so that 
submandibular incisions are made well below the mandible. The cer- 
vical branch supplies platysma. Lesions of the facial nerve, for example 
by tumours of the parotid, cause imilateral drooping of the face with 
loss of the normal skin creases, and it can be shown up by asking the 
patient to whistle or close up his eyes tightly. 

• The trigeminal nerve: sensory to the whole face (Fig. 67.3) except 
for the area over the parotid (see Chapter 57). 



The face and scalp 149 



Temporal branch 
Zygomatic branch 



Superficial 
temporal artery 

Parotid duct 



Lesser occipital nerve 
Greater auricular nerve 
Posterior auricular vein 
Retromandibular vein - 




Supraorbital artery and nerve 

Supratrochlear artery 

Facial artery 
Infraorbital nerve 
Facial vein 

Labial branches 

Buccal branch 

Mental nerve 

Marginal mandibular branch 

Cervical branch 



Fig.67.3 

The principal nerves and blood vessels of the face 



Blood vessels of the face (Fig. 67.3) 

• The facial artery (see p. 133): enters the face by passing over tlie 
lower border of the mandible at the anterior border of masseter. It has a 
tortuous course, passes close to the corner of the mouth and then along- 
side the nose to end near the medial angle of the eye. It anastomoses 
freely across the midline and with other arteries on the face. 

• The facial vein: follows a straighter path than the artery and anasto- 
moses at the medial angle of the eye with the ophthalmic veins and thus 
with the cavernous sinus. This is a possible route for infection to travel 
from the face to the sinus. 

The eye 

• The conjunctiva: covers the surface of the eye and is reflected onto 
the inner surface of the eyelids, the angle of reflection forming the 
fornix of the conjunctival sac. The conjunctiva over the siuface of the 
eye is thin so that a conjunctival haemorrhage is bright red as the blood 
remains ftdly oxygenated. 



• The tarsal plates: are composed of dense fibrous tissue, more com- 
pact in the upper than the lower eyelid. Outside these are the muscle 
fibres of the palpebral part of the orbicularis oculi, some loose areolar 
tissue and skin. Partly embedded in the deep surface of the tarsal plates 
are the tarsal (Meibomian) glands which open onto the edge of the eye- 
lids and produce a modified form of sebum. 

• The lacrimal gland: is in the upper lateral part of the orbit, lying in a 
shallow hollow in the bone. Its secretions pass through 9-12 ducts into 
the superior fornix of the conjunctiva and thence across the eye to the 
medial angle (canthus). From here the tears pass into the lacrimal 
pimcta, two minute openings in the upper and lower eyelids, and thence 
into the lacrimal sac lying in a groove in the lacrimal bone. This drains 
the tears into the nasolacrimal duct which opens into the inferior mea- 
tus of the nose. 



150 Head and neck 



Nerves 



Arteries 




Supratrochear- 
Supraorbital 

Auriculotemporal 



Lesser occipital 
Greater occipital 



Fig.67.4 

The nerves and blood vessels of the scalp. 
The dotted line shows a temporal 'flap' 



Supratrochear 
Supraorbital 

Superficial temporal 



Posterior auricular 



Occipital 



The scalp 

The scalp is made up of five layers which form a useful mnemonic: 

• Skin. 

• Cutaneous fat and connective tissue. 

• Aponeurosis (epicranial): this is a tough sheet of dense connective 
tissue into which are inserted the occipital and frontal bellies of the 
occipitofrontalis muscle. 

• Loose areolar tissue: this forms a plane of cleavage in head injuries 
so that, in some cases, 'scalping' can occur. It also forms a plane in 
which blood can spread for a long distance. 

• Pericranium: the periosteum of the outside of the skull. 



Blood vessels and nerves 

All enter from the periphery and are shown in Fig. 67.4. The vessels 
anastomose freely. Incisions can be centred on one artery which can 
keep a large flap of skin viable. 

Emissary veins 

Small veins that pass through the skull and unite the veins of the scalp 
with the intracranial veins. They form a possible route for infection to 
reach the cranial cavity. 



The face and scalp 151 



68 The cranial cavity 




F\q.6&A 

The principal folds of serous dura 



Cerebral veins 
Falx cerebri 

Tentorium cerebelli 



Diaphragma sellae 



Cerebral vein 
draining into lacuna 

Arachnoid villus 

EJrain covered by pia 



Endothelium of superior 
sagittal sinus 




Emissary vein 
Fibrous dura 
Serous dura 



Arachnoid 
Pia 

Inferior 
sagittal sinus 



Fig.66.2 

A cross-section through the superior sagittal sinus to show the arachnoid villi 
projecting into the sinus 



Abducent nerve 

Internal carotid artery 
Diaphragma sellae 




Oculomotor nerve 
Trochlear nerve 
Ophthalmic branch 
Maxillary branch 
Mandibular branch 

Fig.66.3 

A cross-section through the cavernous sinus 



Pituitary 
Fibrous dura 

Sphenoidal sinus 

Endothelium of 
cavernous sinus 

Emissary vein 



The meninges 

The meninges comprise the dura, pia and arachnoid mater. The cere- 
brospinal fluid is produced in the choroid plexuses of the lateral, 3rd 
and 4th ventricles of the brain and leaves through the three foramina in 
the roof of the 3rd ventricle. It passes into the subarachnoid space 
between the arachnoid and pia and serves to protect the brain and spinal 
cord. 

• The dura mater (Fig. 68.1): \he fibrous layer is closely adherent to 
the bone but the serous layer separates from the fibrous layer in places 



to form the dural venous sinuses which are lined by endothelium. It 
also forms two large sheets— the /a/x cerebri and the tentorium cere- 
belli (see below). 

• The arachnoid mater: deep to the dura. Bridges over the sulci and 
fissures of the brain. The subarachnoid space contains the cerebrospinal 
fluid. 

• The pia mater: follows the contours of the brain, dipping into the 
sulci. 



152 Head and neck 



The falx cerebri 

The/a/.Y cerebri projects down in the sagittal plane to separate partially 
the two cerebral hemispheres. It tapers to a point anteriorly but pos- 
teriorly it is attached to the tentorium. The superior sagittal sinus 
(Fig. 68.2) is in its attached border and the inferior sagittal sinus is in its 
free border. Veins from the cerebral hemispheres drain into the superior 
sagittal sinus or into diverticula from it, the lacunae laterales. In places 
the underlying arachnoid sends small outgrowths through the serous 
dura to project into the sinus. These are the arachnoid villi and they are 
the site of absorption of cerebrospinal fluid into the bloodstream. In 
later life they clump together to form arachnoid villi which make 
indentations in the skull. 

The tentorium cerebelli 

The tentorium cerebelli forms a roof over the posterior cranial fossa 
and the cerebellum. Its free border is attached to the posterior clinoid 
processes and through the opening passes the brainstem. The trans- 
verse sinuses are in the attached border of the tentorium. 



There are two smaller projections of serous dura— the /a/.r cerebelli 
between the two cerebellar hemispheres and the diaphragma sellae 
which forms a roof over the pituitary fossa and the pituitary gland. 

The cavernous sinus (Fig. 68.3) 

The cavernous sinus lies on either side of the pituitary fossa and the 
body of the sphenoid. Like the other venous sinuses, it is formed by a 
layer of serous dura lined by endothelium. In addition, a layer of serous 
dura from the posterior cranial fossa projects forwards into the side of 
the cavernous sinus to form the cavum trigeminale. 

Contents 

• Internal carotid artery: seep. 133. 

• Oculomotor nerve: seep. 127. 

• Trochlearnerve: seep. 127. 

• Abducent nerve: seep. 131. 

• Three divisions of the trigeminal nerve: seep. 129. 



The cranial cavity 153 



69 The orbit and eyeball 



Frontal 

Lacrimal 

Trochlear 

Oculomotor 

Abducent 

Nasociliary 




Superior oblio[ue 

Optic nerve 

Central artery of retina 

Ophthalmic artery 

Oculomotor 

Fibrous ring 

Inferior oblio[ue 

Fig.69.1 

The back of the orbit to show the origins of the muscles that move the eyeball 
and the nerves that enter through the superior orbital fissure and the optic canal 



Axis of Axis of 
orbit eyeball 




Superior obliq^ue 
Medial rectus 
Superior rectus 
Lateral rectus 

Levator palpebrae 
superioris 



Fig.69.2 

The muscles that move the eyeball seen from above 



Supratrochlear 
Dorsal nasal 
Supra-orbital 
Anterior ciliary 



Lacrimal 



Arteries 



Nerves 



Long posterior ciliary 
Short posterior ciliary 

Optic nerve 




Ethmoidal 



Ophthalmic 



Fig.69.3 

The arteries and nerves of the orbit 




Supra-orbital 
Supratrochlear 

Infratrochlear 
Ethmoidal 



Long ciliary 

Short ciliary 

Ciliary ganglion 

Frontal 

Optic 

Nasociliary 

Lacrimal 



154 Head and neck 



Cornea 

Ac|_ueous 

humour 



Cnoro\d 
Sclera 



Optic nerve 
Sheath of - 
meninges 




Iris 
Conjunctiva 



Retina 

Vitreous 

body 

Fovea 

centralis 

Central 

artery 



The bony walls of the orbit have already been described (Chapter 55). 

The orbit contains the eyeball and optic nerve, along with the 3rd, 4th 
and 6th cranial nerves and the three branches of the ophthalmic division 
of the trigeminal nerve. 

The parasympathetic ciliary ganglion is attached to a branch of the 
oculomotor nerve. 

The ophthalmic artery supplies the contents of the orbit, and the 
superior and inferior ophthalmic veins drain it, passing through the 
superior orbital fissure. 

• The superior orbital fissure: this slit-like opening is divided into 
two parts by the fibrous ring that forms the origin of the main muscles 
that move the eyeball. The ring also includes the optic canal (Fig. 69.1). 
It is the portal of entry for a number of important structures: 

• Above the ring — frontal, lacrimal and trochlear nerves. 

• Within the ring — two divisions of the oculomotor, the nasociliary 
and the abducent nerves. 

• The optic canal: transmits the optic nerve and the ophthalmic artery. 

• The inferior orbital Assure: transmits the maxillary nerve and some 
small veins. 

• The muscles of the eyeball (Fig. 69.2), except for the inferior 
oblique, take origin from the fibrous ring and spread out to form a fibro- 
muscular cone that encloses the eyeball. The ring also gives origin to 
the levator palpebrae superioris which is inserted into the upper eyelid 
and opens the eye. 

• The lateral rectus — turns the eyeball laterally. 

• The medial rectus — turns the eyeball medially. 

• The superior /'efft/.?— because of the different long axes of the orbit 
and of the eyeball, turns the eye upwards and medially. 

• The inferior rectus— for the same reason, turns the eye downwards 
and medially. 

• The superior oblique — passes along the medial wall of the orbit, 
turns sharply through a fibrous pulley and is inserted into the upper 
part of the eyeball, below the superior rectus. It turns the eye down- 
wards and laterally. When this muscle and the inferior rectus con- 
tract together, the eye turns directly downwards. 

• The inferior oblique — arises from the floor of the orbit, passes 
under the eyeball like a hammock and is inserted into its lateral 
side. It turns the eye upwards and laterally. Together with the supe- 
rior rectus it turns the eye directly upwards. 

• Thenervesupply of the orbital muscles: the lateral rectus ('abduc- 
tor') of the eye is supplied by the abducent nerve, the superior rectus 
(the 'muscle with the pulley') is supplied by the trochlear nerve. All the 
others, including levator palpebrae superioris, are supplied by the ocu- 
lomotor nerve . 



Sinus venosus sclerae 
Conjunctiva — 

Circularand — 
radiating 
ciliary muscles 

Sclera 

Cnoro\(i — 




Cornea 

Anterior 

chamber 

Iris 

Posterior 

chamber 

Lens 



Suspensory 
ligament 



Fig.69.4 

The eyeball in section and detail of the iridocorneal angle 

• The other nerves and the vessels of the orbit are shown in Fig. 
69.3. The most important branch of the ophthalmic artery is the central 
artery of the retina which enters the optic nerve and is the only blood 
supply to the retina. 

The eyeball (Fig. 69.4) 

The eyeball is composed of three layers. The outermost is a tough 
fibrous layer, the sclera. Within this is the very vascular choroid and 
inside this again is the sensory part of the eye, the retina . Anteriorly, the 
sclera is replaced by the transparent cornea, which is devoid of vessels 
or lymphatics and can therefore be transplanted. At the corneoscleral 
junction there is an important venous structure, the sinus venosus scle- 
rae {canal of Schlemm). Behind the cornea, the choroid is replaced by 
the ciliary body, with its radially arranged ciliary processes, and the 
iris. The ciliary body contains the circular and radial smooth muscle 
fibres of the ciliary muscle, supplied by parasympathetic fibres from the 
ciliary ganglion via the oculomotor nerve. These, when they contract, 
relax the lens capsule and allow the lens to expand; thus they are used in 
near vision. The iris contains smooth muscle fibres of the dilator pupil- 
lae and sphincter pupillae, supplied, respectively, by the sympathetic 
system (from the superior cervical ganglion) and the parasympathetic 
system (from the oculomotor nerve via the ciliary ganglion). The lens 
lies behind the pupil and is enclosed in a delicate capsule. It is sus- 
pended from the ciliary processes by the suspensory ligament. 

The ciliary body secretes the aqueous humour into the posterior 
chamber of the eye (lying behind the pupil). The aqueous then passes 
through the pupil into the anterior chamber and is reabsorbed into the 
sinus venosus sclerae. Any interference with this process can give rise 
to a dangerous increase in intra-ocular pressure, a condition known as 
glaucoma. 

Behind the lens the eyeball is occupied by the gelatinous vitreous 
humour. 

The retina consists of an inner nervous layer and an outer pigmented 
layer. The nervous layer has an innermost layer of ganglion cells whose 
axons pass back to form the optic nerve. Outside this is a layer of bipo- 
lar neurones and then the receptor layer of rods and cones. Near the 
posterior pole of the eye is the yellowish macula lutea, the receptor area 
for central vision. The optic disc is a circular pale area marking the end 
of the optic nerve and the site of entry of the central artery of the retina. 
This divides into upper and lower branches, each of which gives tem- 
poral and nasal branches. Since the subarachnoid space and its contained 
cerebrospinal fluid reach to the back of the eyeball, any increase in 
intracranial pressure can give rise to changes in the optic disc which 
are visible through an ophthalmoscope . 



The orbit and eyeball 155 



70 The ear, and lymphatics and surface anatomy of the head and neck 



Stapes 

Facial nerve 
Aditus 



Ridge produced by lateral semicircular canal 
Tegmen tympani 

Geniculate ganglion 



Incus 
Malleus 



Chorda 
tympani 

Tympanic 
membrane 




Round window 
Internaljugularvein 



Fig.70.1 

A diagram representing the middle ear as an opened-out box 



Greater petrosal nerve 
Lesser petrosal nerve 

Auditory tube 
Tympanic plexus 
Promontory 

Internal carotid artery 



Tympanic branch 
Glossopharyngeal nerve 



Anterior Posterior 



Parsflaccida 



Lateral process 
of malleus 




Long process of 
incus 

Handle of malleus 




Cone of light 



Fig.70.2 

The left tympanic membrane, as seen through an auriscope. 
The 'cone of light' is caused by the reflection of the light of 
the auriscope 



Buccal 

Pre-auricular 
Post-auricular 
Occipital 

Submental 
Submandibular 
Upper deep cervical 

Infrahyoid 
Paratracheal 

Inferior deep cervical 



Upper deep cervical 
Sternocleidomastoid 
Lower deep cervical 



Fig.70.3 

The princi 
The inset 



pal groups of lymph nodes of the head and neck arranged as a triangle, 
(right) shows the two major groups into which the others eventually drain 



156 Head and neck 



The ear 

The ear is subdivided into tlie outer ear, tlie middle ear and tlie inner ear. 

The outer ear 

The outer third of this is cartilaginous and the inner two-thirds is bony. 
Lined by skin with ceruminous (wax) glands. 

The middle ear 

This has four walls, a roof and a floor. It can therefore be represented 
diagrammatically by an opened-out box (Fig. 70. 1). 

• The lateral wall: 

• The tympanic membrane (Fig. 70.2) — the handle of the malleus 
embedded in its middle layer. This is crossed by the chorda tym- 
pani, above which is \he pars flaccida. The 'cone of light' is the 
reflection of the light from the auriscope. 

• The epitympanic recess (aH/c)— the part of the middle ear cavity 
above the tympanic membrane. 

• The ossicles: the malleus, incus and stapes — the stapes engages 
with the oval window. The ossicles transmit vibrations of the mem- 
brane to the inner ear. 

• The medial wall: 

• The promontory — a bulge produced by the first turn of the cochlea. 

• The oval window — leads into the iimer ear. 

• The facial nerve — runs backwards and then downwards in a bony 
canal in the medial wall. It bears the geniculate ganglion and gives 
off the chorda tympani. 

• The anterior wall: Xhe. pharyngotympanic (Eustachian) tube opens 
onto the anterior wall and leads down to the nasopharynx. Its function 
is to equalize the pressure between the middle ear and the pharynx. 

• The posterior wall: the aditus leads backwards into the mastoid 
antrum, a cavity in the mastoid bone which, in turn, leads into the mas- 
toid air cells. 

• The roof: the tegmen tympani, a thin plate of bone that separates the 
middle ear from the middle cranial fossa. 

• The floor: separates the middle ear from the internal carotid artery 
and the internal jugular vein. 

The inner ear 

The inner ear is involved in both hearing and balance. It consists of two 
components: 

• The osseous labyrinth: comprises the vestibule, the semicircular 
canals and the cochlea. The labyrinth itself consists of spaces in the 
petrous temporal bone and it contains the membranous labyrinth. 

• The membranous labyrinth: comprises the utricle and saccule (in 
the vestibule), the semicircular ducts (in the semicircular canals) and 
the duct of the cochlea (in the cochlea). The utricle and saccule are con- 
cerned with the sense of position and the semicircular ducts are con- 
cerned with the sensation of motion. The cochlear duct is the organ of 
hearing. All are supplied by the vestibulocochlear (auditory) nerve. 

The lymphatics of the head and neck (Fig. 70.3) 

• Upper deep cervical nodes (jugulodigastric nodes): these are situ- 
ated between the upper end of sternomastoid and the angle of the 



mandible and also deep to sternomastoid. They drain the head and the 
upper part of the neck, directly or indirectly (but there are no lym- 
phatics in the cranial cavity). 

• The lower deep cervical nodes {jugulo-omohyoid nodes): in the 
posterior triangle between the lower end of sternomastoid and the clav- 
icle. They drain the lower part of the neck and also receive lymph from 
the upper deep cervical nodes, from the breast and some of the lymph 
from the thorax and abdomen. The efferents from this group drain into 
the thoracic or left lymph duct via the jugular trunk. 

• Smaller groups of nodes are shown in Fig. 70.3. 

• The lymph drainage of the tongue: the tip of the tongue drains into 
the submental nodes. The rest of the anterior two-thirds drains into the 
submandibular nodes, some crossing the midline and some passing 
directly to the upper deep cervical nodes. The posterior two-thirds 
drains directly into the upper deep cervical nodes. 

• The lymph drainage of the larynx: above the vocal cords the larynx 
drains into the infrahyoid nodes and thence to the upper deep cervical 
group. Below the cords, drainage is to the paratracheal and inferior 
deep cervical nodes. 

Surface anatomy of the head and neck 

• The middle meningeal artery: the anterior branch may be exposed 
at a point 4 cm above the midpoint of the zygomatic arch. The posterior 
branch may be represented on the surface by a pencil placed behind the 



The face 

• The supraorbital, infraorbital and mental nerves: all lie on a ver- 
tical line passing between the two premolar teeth. 

• The facial artery can be felt on the mandible at the anterior border of 
the masseter. 

• The superficial temporal artery is just in front of the tragus of the 
ear. 

• The parotid duct follows the middle part of a line from the tragus of 
the ear to the middle of the upper lip. It hooks over the anterior border 
of the masseter where it can be easily felt. 

The neck 

• The sternomastoid muscle (with the external jugular vein on its sur- 
face) may be made to contract by asking the patient to turn his head to 
the opposite side against resistance. 

• The trunks of the brachial plexus can be palpated in the angle 
between the sternomastoid and the clavicle. 

• The subclavian artery is palpable by deep pressure behind the 
middle of the clavicle. A cervical rib may also be palpable. 

• The hyoid bone, and the thyroid and cricoid cartilages are easily 
felt. The larynx, and any swellings associated with it, move upwards 
on swallowing, as does the thyroid gland. Thyroglossal cysts move 
upwards when the tongue is protruded. 

• The trachea is palpable in the suprasternal notch. 

• The common carotid artery can be felt in front of sternomastoid 
and can be compressed against the transverse process of the 6th cer- 
vical vertebra (carotid tubercle). 



The ear, and lymphatics and surface anatomy of the head and neck 157 



71 The spine 





True 

transverse 

process 

Costal 
element 

Anterior 

and posterior 

tubercles of 

transverse 

process 
Fig.71.1 

A cervical vertebra. 

The anterior tubercles of the transverse processes 
represent the costal elements 



Transverse 
process 
Head of rib 



Superior 
articular facet 
Foramen 
transversarium 



Facet 
for rib 

Spine 




Lamina 



Pedicle 



Fig.71.3 

Thoracic vertebra. 
The articular facets lie on 
the arc of a circle, thus 
permitting rotation 



Demifacetfor rib 

Intervertebral foramen 
Intervertebral disc 
Body 

Spine 

Transverse process 

Facet for rib 

Articular facet (superior) 

Demifacetfor rib 

Vertebral canal 
Body 




Facet for 

occipital 

condyles 



Facet for dens 

Dens 

Position of transverse 
ligament 




Transverse 
process 

Foramen 
transversarium 
Groo'^e for 
vertebral artery 
Posterior 
tubercle 

The upper surface of the atlas. 

The dotted area shows the position of the dens 

and the dotted line indicates the transverse 

ligament 



Fig.71.2 



Ligamentum 
flavum 



Interspinous ligament 
Supraspinous ligament 



Spine 



Superior 
articular 
facet 

Body 



Fig.71.4 

A lumbar vertebra. 

The direction of the articular facets 

does not permit rotation 




Intertransverse 
ligament 



Anterior longitudinal 
ligament 

Intervertebral disc 
Posterior longitudinal ligament 
Fig.71.5 
The ligamentsjoining two adjacent vertebrae 



158 Spine and spinal cord 



There are 12 thoracic, five lumbar, five sacral and 3-5 coccygeal ver- 
tebrae. They are held together by ligaments, intervertebral discs and 
synovial joints between the articular processes. The weight-bearing 
portion of the vertebra is the body so that the size of the vertebral bodies 
increases from above downwards and when one of the bodies is dis- 
eased it will eventually collapse. The bodies contain red bone marrow 
so that the veins that drain them (basivertebral veins) produce large 
foramina on the backs of the bodies. 

• Cervical vertebrae (Fig. 71.1): smidlbodies, bifid spines, transverse 
processes with anterior and posterior tubercles and a foramen 
transversarium for the passage of the vertebral artery. The body of the 
first vertebra (atlas) fuses with that of the second (axis) during develop- 
ment to produce its dens {odontoid process) which is held in place by a 
transverse ligament (Fig. 71.2). 

• Thoracic vertebrae (Fig. 71.3): heart-shaped bodies, upper and 
lower demifacets for the heads of the ribs, long downturned spine, long 
transverse processes with a facet for the tubercles of the rib. 

• Lumbar vertebrae (Fig. 71.4): a massive body, large transverse 
processes, a triangular vertebral canal and large, backwardly project- 
ing spines so that a needle may be inserted between them in the opera- 
tion of lumbar puncture. The articular facets face mediolaterally so 
that they prevent rotation. 

• Sacral vertebrae (Fig. 23.3): fused together to form the sacrum. 

The intervertebral joints 

The upper and lower surfaces of the bodies are covered with hyaline 
cartilage and are separated by the fibrocartilaginous intervertebral 
discs. Each disc has a peripheral fibrous ring {annulus fibrosus) and a 
central more spongy nucleus pulposus which lies nearer to the back 
than to the front of the disc. The nucleus pulposus is rich in gly- 
cosaminoglycans so that it has a high water content, but this diminishes 
with increasing age. The nucleus may then herniate through the annulus 
fibrosus, passing backwards (compressing the spinal cord), posterolat- 
erally (compressing a spinal nerve) or upwards (into a vertebral 
body — a Schmorl's node). The discs are thickest in the lumbar and cer- 
vical regions, so that these are the regions of most movement. 

The vertebrae are also held together by ligaments that join each of 
the components of the vertebrae (Fig. 7 1 .5) except for the pedicles (the 
spinal nerves have to pass between these in the intervertebral foram- 
ina). Thus there are: 



• Anterior and posterior longitudinal ligaments joining the front 
and back of the bodies (the posterior ligaments thus lie within the ver- 
tebral canal). 

• Supraspinous and interspinous ligaments. 

• Intertransverse ligaments. 

• Ligamenta flava (which contain much elastic tissue and join the 
laminae). 

• Capsular ligaments of the synovial joints between the articular 
processes. 

Curves of tlie spine 

In the fetus, the whole developing spine is curved so that it is concave 
forwards (primary curvature). A few months after birth the baby begins 
to hold its head up and the cervical spine develops a forward convexity 
(secondary curvature). Later in the first year the baby begins to stand 
up and another forward convexity develops in the lumbar region (sec- 
ondary curvature). The primary curves are mainly due to the shape of 
the vertebral bodies but the secondary curves are due to the shape of the 
intervertebral discs. 

Movements of ttie spine 

• Cervical spine: movement is free in the cervical region of the spine: 
flexion and extension, side flexion (associated with rotation to the 
opposite side) and rotation. In rotation of the head the atlas rotates 
around the dens of the axis, and in flexion of the head the occipital 
condyles move on the articular facets of the atlas. 

• Thoracic spine: movement is somewhat restricted by the thinner 
intervertebral discs and the presence of the ribs. Rotation, however, is 
free. 

• Lumbar spine: flexion and extension are free but rotation is almost 
absent because of the direction of the articular facets. Side flexion also 
occurs. 

Spina bifida 

Each vertebra develops in three parts — the body and the two halves of 
the neural arch. These ossify in cartilage and, at birth, the three parts 
are .still separate but they soon fuse. Failure of such fusion gives rise to 
the condition of spina bifida. This may be symptomless (spina bifida 
occidta) although the site of the lesion may be marked by a tuft of hair. 
If the defect is large, the meninges or even the spinal cord may herniate 
onto the surface (meningocoele) and this may produce neurological 
symptoms. 



The .spine 159 



72 The spinal cord 



C3 



C4 



/CS 



L4- 



L2 



L3 



L5 



SI- 




SI 



L3- 



L4- 





Fig.72.1 

A map of the dermatomes. 
The small diagram shows the regular arrangement 
of dermatomes in the embryo, before the limbs 
become fully developed 



In the fetus, the spine and the spinal cord are the same length but, since 
the spine grows more quickly than the spinal cord, the lower end of the 
cord gradually retreats upwards, reaching the level of L3 at birth and 
the lower border of LI in the adult. For this reason, too, the anterior and 
posterior nerve roots become more and more oblique from above down- 
wards so the lumbar and sacral nerve roots form a bundle, the caitda 
equina, which occupies the lower part of the spinal canal. The posterior 
root ganglia occupy the intervertebral foramina so that the roots do 
not unite until after this point. The spinal cord itself ends as the filum 
terminale, a thin fibrous band which is included in the cauda equina. 



The spinal cord shows two enlargements in the cervical and lumbar 
regions, corresponding to the origins of the nerves that make up the 
limb plexuses. It is for this reason that the vertebral canal is larger in 
these regions, and they are also the regions of the greatest mobility. 
• The meninges: the meninges— the diira,pia and arachnoid— ^re con- 
tinuous with those of the cranial cavity so that the subarachnoid space 
is also continuous and cerebrospinal fluid may be drained from the sys- 
tem or its pressure measured, by lumbar puncture. The subarachnoid 
space ends at the level of S2. 



160 Spine and spinal cord 



• The blood supply of the spinal cord: the spinal cord is supplied 
with blood by spina! arteries that are derived from the vertebra!, inter- 
costa!, !umbar and iatera! sacra! arteries. Each artery divides into dor- 
sa! and ventra! branches that follow the corresponding nerve roots to 
the spinal cord where they form longitudinally arranged anterior and 
^si\re.A posterior spina! arteries. These longitudinal anastomoses, how- 
ever, are incomplete and the spinal arteries themselves vary in size. The 
largest are in the lower thoracic and upper lumbar regions, and the 
blood supply of the cord may be jeopardized if some of these larger 
spinal arteries are damaged, for example in resection of the thoracic 
aorta. 

The spinal nerves 

As has been described in Chapter 2, the spinal nerves from T2 to LI 
supply segmental areas of skin and muscles but elsewhere they form 
plexuses so that the areas supplied by each nerve become more complic- 
ated. Each named perip!iera! nerve may contain components of more 
than one spina! nerve and each spina! nerve may contribute fibres to 



more than one peripliei-a! nerve. However, the area of skin supplied by 
any one spinal nerve (a dermatome) can be mapped out and these are 
shown in Fig. 72. 1 . Knowledge of the dermatome map is of great value 
in diagnosing lesions of the spinal nerves but it must be remembered 
that these areas are subject to some variation from one person to 
another and there is also a good deal of overlap. Thus a lesion of, say, 
T4 may cause little or no loss of sensation because of overlap with T3 
andT5. 

Similarly, certain groups of muscles {myotomes) can be recognized 
as being supplied by particular spinal nerves. For example, C5 supplies 
the abductors of the shoulder, the flexors of the elbow and the supin- 
ators so that a lesion of this nerve or of the upper trunk of the brachial 
plexus will cause the arm to be held in a position of adduction of the 
shoulder, extension of the elbow and pronation {Erb-Diichenne para- 
iysis). Similarly, Tl supplies the small muscles of the hand so that a 
lesion of this nerve, due perhaps to the presence of a cervical rib, will 
cause global wasting of the hand muscles. 



T!ie spina! cord 161 



Muscle index 



The abdomen 

All the muscles of the anterior abdominal wall serve to protect the vis- 
cera by their contraction, to produce movement and to increase the 
intra-abdominal pressure, as in defecation, coughing, parturition, etc. 
All these muscles are supplied by the lower six thoracic and the first 
lumbar nerves. 

• External oblique 

Origin: From the outer surfaces of the lower eight ribs to the iliac crest 

as far forward as the anterior superior spine. 

Insertion: The free lower border forms the inguinal ligament between 

the anterior superior iliac spine and the pubic tubercle. The muscle 

becomes aponeurotic and reaches the midline where it interdigitates 

with the opposite side to form the linea alba. The superficial inguinal 

ring is a gap in the aponeurosis above and medial to the pubic tubercle. 

The aponeurosis contributes to the anterior rectus sheath. 

Actions: Flexion of the spine, side flexion and rotation of the trunk— the 

right external oblique produces rotation to the left. 

• Internal oblique 

Origin: From the thoracolumbar fascia, the iliac crest and the lateral 

half of the inguinal ligament. 

Insertion: Into an aponeurosis which is attached to the costal margin 

and to the linea aspera, after splitting to enclose the rectus abdominis, 

thus contributing to the rectus sheath. The lower fibres from the 

inguinal ligament contribute to the conjoint tendon which is attached to 

the pubic crest and the pectineal line. 

Actions : Flexion of the spine, side flexion and rotation of the trunk— the 

right internal oblique produces rotation to the right. 

• Transversus abdominis 

Origin: From the thoracolumbar fascia, the iliac crest and the lateral 
one third of the inguinal ligament. Also from the inner surfaces of the 
lower six ribs, interdigitating with the diaphragm. 
Insertion: The aponeurosis passes to the linea aspera, contributing to 
the rectus sheath. The lower fibres help to form the conjoint tendon. 
Actions: Most of the fibres are transverse and thus pull in and flatten the 
abdominal wall. 

• Rectus abdominis 

Origin: From the anterior surfaces of the 5th, 6th and 7th costal 

cartilages. 

Insertion: The pubic crest and tubercle and the front of the symphysis. 

There are three tendinous intersections in the upper part of the muscle 

which are adherent to the anterior rectus sheath. 

Actions: The muscle is enclosed in the rectus sheath. A strong flexor of 

the trunk, it can also tilt the pelvis backwards. In a person lying prone, 

rectus contracts when the head is lifted from the pillow or when the leg 

is raised from the bed. 

For further important details of the muscles of the anterior abdom- 
inal wall, see the inguinal canal and the rectus sheath (p. 30). 

• The diaphragm 

Origin: From the inner surfaces of the lower six ribs, from the back of 
the xiphisternum, from the right and left crura which are attached, 
respectively, to the upper three and the upper two lumbar vertebrae, and 
from the medial and lateral arcuate ligaments which bridge over the 
psoas major and quadratus lumborum. 



Insertion: The fibres (striated muscle) are inserted into the central 

tendon. 

Actions: The diaphragm is involved in respiration. When the muscle 

fibres contract, the diaphragm is lowered, thus increasing the vertical 

dimension of the thorax. In the later stages of contraction, using the 

liver as a fulcrum it raises the lower ribs, thus increasing the width of 

the lower thorax. At the same time, it increases the intra-abdominal 

pressure and is thus used in expulsive efforts— defecation, micturition, 

parturition, etc. 

Nerve supply: Phrenic nerve (C3, 4 and 5). 

• Quadratus lumborum 

Origin: From the posterior part of the iliac crest. 
Insertion: To the 12th rib. 
Action: Side flexion of the trunk. 
Nerve supply: Adjacent lumbar nerves. 

• Psoas major: see lower limb (p. 165). 

The upper limb 

• Latissimus dorsi 

Origin: From the spines of the lower six thoracic vertebrae, the lumbar 

spines via the thoracolumbar fascia and the medial part of the iliac 

crest. 

Insertion: To the floor of the intertubercular sulcus, curving round teres 

major. 

Actions: Adduction and medial rotation of the arm. Can hold up the 

lower limb girdle as in crutch walking. 

Nerve supply: Thoracodorsal nerve. 

• Serratus anterior 

Origin: From the lateral surfaces of the upper eight ribs. 

Insertion: Into the medial border of the scapula. 

Actions: Protraction of the scapula and rotation so that the glenoid 

points upwards, thus helping in abduction of the upper limb. Helps to 

keep the scapula in contact with the chest wall. 

Nerve supply: Long thoracic nerve. 

• Levator scapulae 

Origin: From the transverse processes of the upper cervical vertebrae. 
Insertion: To the medial border of the scapula above the spine. 
Action: Elevates the scapula. 
Nerve supply: C3 and 4. 

• The rhomboids 

Origin: From spines of thoracic vertebrae. 
Insertion: To the medial border of the scapula. 
Action: Bracing back the scapula. 
Nerve supply: Dorsal scapular nerve. 

• Trapezius: Seep. 167. 

• Pectoralis major 

Origin: From the sternum and the upper six costal cartilages and from 

the medial half of the clavicle. 

Insertion: To the lateral lip of the intertubercular sulcus. 

Actions: Adduction, flexion and medial rotation of the arm. 

Nerve supply: Medial and lateral pectoral nerves. 

• Pectoralis minor 

Origin: From the 3rd, 4th and 5th ribs. 



162 Muscle index 



Insertion: To the coracoid process. 
Action: Depresses the tip of the shoulder. 
Nerve supply: Medial and lateral pectoral nerves. 

• Deltoid 

Origin: From the lateral third of the clavicle, the acromion and the 

spine of the scapula. 

Insertion: To the deltoid tubercle on the lateral surface of the humerus. 

Actions: Abduction of the upper limb (assisted by supraspinatus and 

serratus anterior), flexion (anterior fibres) and extension (posterior 

fibres) of the arm. 

Nerve supply: Axillary nerve. 

• Teres major 

Origin: From the lower angle of the scapula. 
Insertion: To the medial lip of the intertubercular sulcus. 
Actions: Adduction and medial rotation of the arm. 
Nerve supply: Lower subscapular nerve. 

• The rotator cuff 

Consists of subscapularis. supraspinatus, infraspinatus and teres 
minor. Acting together, these muscles maintain the stability of the 
shoulder joint as well as having their own individual actions, as 
follows: 

• Subscapularis 

Origin: From the subscapular fossa. 

Insertion: Passes in front of the shoulder joint to the lesser tuberos- 
ity of the humerus. 
Action: Medial rotation of the arm. 
Nerve supply: Subscapular nerves. 

• Supraspinatus 

Origin: From the supraspinous fossa. 

Insertion: To the top of the greater tuberosity of the humerus. 

Action: Initiates abduction of the arm. 

Nerve supply: Suprascapular nerve. 

• Infraspinatus 

Origin: From the infraspinous fossa. 
Insertion: To the back of the greater tuberosity. 
Action: Lateral rotation of the arm. 
Nerve supply: Suprascapular nerve. 

• Teres minor 

Origin: From the lateral border of the scapula. 
Insertion: To the humerus below infraspinatus. 
Action: Lateral rotation of the arm. 
Nerve supply: Axillary nerve. 

• Coracobrachialis 

Origin: From the coracoid process along with the short head of biceps. 
Insertion: To the medial side of the humerus. 
Action: Moves the arm upwards and medially. 
Nerve supply: Musculocutaneous nerve. 

• Biceps bracliii 

Origin: Long head from the supraglenoid tubercle and short head from 

the coracoid process (with coracobrachialis). 

Insertion: To the radial tuberosity and, via the bicipital aponeurosis, 

into the deep fascia of the forearm. 

Actions: Flexion and supination of the forearm. 

Nerve supply: Musculocutaneous nerve. 

• Bracliialis 

Origin: From the front of the lower part of the humerus. 

Insertion: To the tubercle on the ulna just below the coronoid process. 

Action: Flexion of the elbow. 

Nerve supply: Musculocutaneous nerve and radial nerve. 



• Triceps 

Origin: Three heads: long from the infraglenoid tubercle, lateral from 
the humerus above the spiral line, and medial from the back of the 
lower part of the humerus. 
Insertion: Into the olecranon. 
Acf/on.- Extensor of the elbow. 
Nerve supply: Radial nerve. 

• Pronator teres 

Origin: From the common flexor origin on the medial epicondyle of the 

humerus. 

Insertion: To the lateral surface of the shaft of the radius. 

Action: Pronation of the forearm. 

Nerve supply: Median nerve. 

• Flexor carpi radialis 

Origin: From the common flexor origin. 
Insertion: To the base of metacarpals 2 and 3. 
Actions: Flexion and abduction of wrist. 
Nerve supply: Median nerve. 

• Palmaris longus 

Origin: From the common flexor origin. 

Insertion: To the flexor retinaculum and the palmar aponeurosis. 

Action: Flexor of the wrist. (Often absent.) 

Nerve supply: Median nerve. 

• Flexor carpi ulnaris 

Origin: From the common flexor origin and the posterior border of the 

ulna. 

Insertion: To the pisiform and thence by the pisometacarpal ligament 

to the 5th metacarpal. 

Actions: Flexion and adduction of the wrist. 

Nerve supply: Ulnar nerve. 

• Flexor digitorum superflcialis 

Origin: From the common flexor origin and the shaft of the radius. 
Insertion: To the sides of the middle phalanges of the four fingers. The 
tendons are perforated by the tendons of flexor digitorum profundus. 
Actions: Flexion of the proximal two phalanges and of the wrist. 
Nerve supply: Median nerve. 

• Flexor pollicis longus 

Origin: From the front of the shaft of the radius. 
Insertion: To the distal phalanx of the thumb. 
Actions: Flexion of all the joints of the thumb. 
Nerve supply: Median nerve. 

• Flexor digitorum profundus 

Origin: From the front of the shaft of the ulna and its posterior border. 
Insertion: To the distal phalanges of the four fingers, the tendons pass- 
ing through those of flexor digitorum superflcialis. 
Actions: Flexion of the fingers and the wrist. 
Nerve supply: Half by the median nerve and half by the ulnar nerve. 

• Pronator quadratus 

Origin: From the lower end of the front of the radius. 
Insertion: To the lower end of the ulna. 
Action: Pronator of the forearm. 
Nerve supply: Median nerve. 

• Brachioradialis 

Origin: From the lateral supracondylar ridge of the humerus. 
Insertion: To the lower end of the radius. 
Action: Flexion of the elbow. 
Nerve supply: Radial nerve. 

• Extensor carpi radialis longus and brevis 

Origin: From the lateral supracondylar ridge of the humerus. 



Muscle index 163 



Insertion: To the bases of the 2nd and 3rd metacarpals. 
Actions: Extension and abduction of the wrist. 
Nerve supply: Radial nerve. 

• Extensor digitorum 

Origin: From the common extensor origin on the lateral epicondyle of 

the humerus. 

Insertion: To the bases of the middle and distal phalanges of the four 

fingers via the extensor expansion. 

Actions: Extension of the fingers and of the wrist (but see also the lum- 

bricals and interossei). 

Nerve supply: Radial (posterior interosseous) nerve. 

• Extensor digit! minimi 

Origin: From the common extensor origin. 

Insertion: To the extensor expansion of the little finger. 

Action: Extension of the little finger. 

Nerve supply: Radial (posterior interosseous) nerve. 

• Extensor carpi ulnaris 

Origin: From the common extensor origin and from the posterior bor- 
der of the ulna. 

Insertion: To the base of the 5th metacarpal. 
Actions: Extension and adduction of the wrist. 
Nerve supply: Radial (posterior interosseous) nerve. 

• Supinator 

Origin: From the lateral side of the humerus and the ulna. 

Insertion: It wraps around the radius from behind to be inserted into the 

upper part of its shaft. 

Action: Supination. 

Nerve supply: Radial (posterior interosseous) nerve. 

• Abductor pollicis longus 

Origin: From the posterior surfaces of the radius and ulna. 
Insertion: To the base of the 1st metacarpal. 
Actions: Abduction and extension of the thumb. 
Nerve supply: Radial (posterior interosseous) nerve. 

• Extensor pollicis brevis 
Origin: From the back of the radius. 

Insertion: To the base of the proximal phalanx of the thumb. 
Action: Extension of the proximal phalanx of the thumb. 
Nerve supply: Radial (posterior interosseous) nerve. 

• Extensor pollicis longus 
Origin: From the back of the ulna. 

Insertion: Into the base of the distal phalanx of the thumb. 
Actions: Extension of all the joints of the thumb. 
Nerve supply: Radial (posterior interosseous) nerve. 

• Extensor indicis 

Origin: From the back of the ulna. 

Insertion: To the side of the extensor digitorum tendon to the index 

finger. 

Action: Helps to extend the index finger. 

Nerve supply: Radial (posterior interosseous) nerve. 

• Abductor pollicis brevis 

Origin: From the flexor retinaculum and adjacent carpal bones. 
Insertion: To the base of the proximal phalanx of the thumb. 
Action: Abduction of the thumb. 
Nerve supply: Median nerve. 

• Flexor pollicis brevis 

Origin: From the flexor retinaculum and adjacent carpal bones. 
Insertion: To the base of the proximal phalanx of the thumb. Its tendon 
contains a sesamoid bone. 
Action: Flexion of the proximal phalanx of the thumb. 



Nerve supply: Median nerve. 

• Opponens pollicis 

Origin: From the flexor retinaculum and adjacent carpal bones. 
Insertion: To the shaft of the 1 st metacarpal. 
Action: Produces opposition of the thumb. 
Nerve supply: Median nerve. 

• Adductor pollicis 

Origin: Oblique head from the bases of metacarpals; transverse head 

from the shaft of the 3rd metacarpal. 

Insertion: To the base of the medial side of the proximal phalanx of the 

thumb. The tendon contains a sesamoid bone. 

Action: Adduction of the thumb. 

Nerve supply: Deep branch of the ulnar nerve. 

• Abductor digiti minimi 
Origin: From the pisiform bone. 

Insertion: To the base of the proximal phalanx of the little finger. 
Action: Abduction of the little finger. 
Nerve supply: Ulnar nerve. 

• Flexor digiti minimi 

Origin: From the flexor retinaculum and adjacent carpal bone. 
Insertion : To the base of the proximal phalanx of the little finger. 
Action: Flexes the proximal phalanx of the little finger. 
Nerve supply: Ulnar nerve. 

• Opponens digiti minimi 

Origin: From the flexor retinaculum and adjacent carpal bones. 
Insertion: To the shaft of the fifth metacarpal. 
Action: Opposition of the little finger. 
Nerve supply: Ulnar nerve. 

• The lumbrical muscles 

Origins: The four muscles arise from the sides of the tendons of the 

flexor digitorum profundus. 

Insertions: To the lateral sides of the dorsal extensor expansions of the 

extensor digitorum tendon. 

Actions: Flexion of the metacarpophalangeal joints and extension of 

the interphalangeal joints. 

Nerve supply: Medial two muscles by the ulnar nerve and lateral two by 

the median nerve. 

• The interossei 

Origins: Dorsal from adjacent sides of four metacarpals and palmar 
from one side of each metacarpal. 

Insertions: Both dorsal and palmar are inserted into the sides of the 
proximal phalanges and the dorsal extensor expansions in such a way 
that the dorsal interossei abduct the fingers and the palmar adduct them 
(Fig. 39.2). 

Actions: Adduction and abduction as above. Both sets of muscles pro- 
duce flexion of the metacarpophalangeal joints and extension of the 
interphalangeal joints, as in the 'precision grip'. 
Nerve supply: All by the deep branch of the ulnar nerve. 

The lower limb 

• Gluteus maximus 

Origin: From the posterior part of the gluteal surface of the ilium, the 

back of the sacrum and its associated ligaments. 

Insertion: To the gluteal tuberosity of the femur (25%) and the ilio- 

tibial tract (75%). 

Actions: Extension and lateral rotation of the thigh. 

Nerve supply: Inferior gluteal nerve. 

• Gluteus medius 

Origin: From the gluteal surface of the ilium. 



164 Muscle index 



Insertion: To the greater trochanter. 

Actions: Abduction and medial rotation of the thigh. 

Nerve supply: Superior gluteal nerve. 

• Gluteus minimus 

Origin: From the gluteal surface of the ilium below gluteus medius. 
Insertion: To the greater trochanter. 

Actions: Abduction and medial rotation of the thigh. The most import- 
ant action of medius and minimus is to prevent the pelvis tilting to the 
unsupported side when taking the weight on one leg, as in walking. 
Nerve supply: Superior gluteal nerve. 

• Tensor fasciae latae 

Origin: From the anterior part of the crest of the ilium. 
Insertion: To the lateral condyle of the tibia via the ilio tibial tract. 
Actions: Extension of the knee joint. Helps the gluteal muscles to pre- 
vent tilting of the pelvis. 
Nerve supply: Superior gluteal nerve. 

• Piriformis 

Origin: From the front of the sacrum. 

Insertion: Into the greater trochanter via the greater sciatic notch. 

Action: Lateral rotation of the thigh. 

Nerve supply: From the sacral plexus. 

• Obturator internus 

Origin: From the inner surface of the hip bone and the obturator 

membrane. 

Insertion: To the greater trochanter via the lesser sciatic notch. 

Action: Lateral rotation of the thigh. 

Nerve supply: From the sacral plexus. 

• Quadratus femoris 

Origin: From the outer surface of the ischial tuberosity. 

Insertion: To the quadrate tubercle on the intertrochanteric crest of the 

femur. 

Action: Lateral rotation of the thigh. 

Nerve supply: From the sacral plexus. 

• Obturator externus 

Origin: From the obturator membrane and the surrounding bone. 
Insertion: To the trochanteric fossa of the femur. 
Action: Lateral rotation of the thigh. 
Nerve supply: Obturator nerve. 

• Iliacus 

Origin: From the concave inner surface of the ilium. 

Insertion: Passes under the inguinal ligament to the lesser trochanter, in 

company with psoas major. 

Action: Flexion of the thigh. 

Nerve supply: Femoral nerve. 

• Psoas major 

Origin: From the transverse processes and the sides of the bodies and 

intervertebral discs of the lumbar vertebrae. 

Insertion: Passes under the inguinal ligament to the lesser trochanter in 

company with iliacus. (Joint muscle often called iliopsoas.) 

Action: Flexion of the thigh. 

Nerve supply: Femoral nerve. 

• Sartorius 

Origin: From the anterior superior iliac spine. 

Insertion: To the medial side of the upper end of the tibia just in front of 

gracilis and semitendinosus. 

Actions: Flexion and abduction of the thigh and flexion of the knee (the 

'tailor's position'). 

Nerve supply: Femoral nerve. 

• Quadriceps femoris: 



• Rectus femoris 

Origin: From the anterior inferior iliac spine {straight head) and 
the upper lip of the acetabulum {reflected head). 

• Vastus medialis 

Origin: From the medial lip of the linea aspera. 

• Vastus lateralis 

Origin: From the lateral lip of the linea aspera. 

• Vastus intermedius 

Origin: From the lateral and anterior surfaces of the femur. 
Insertion of quadriceps: The four parts of quadriceps are inserted into 
the patella and, from here, to the tubercle of the tibia. The patella is thus 
a sesamoid bone in the tendon of quadriceps. 

Actions: Extension and stabilization of the knee. Rectus is also a weak 
flexorof the thigh. 
Nerve supply: Femoral nerve. 

• Pectineus 

Origin: From the superior ramus of the pubis. 

Insertion: To the back of the femur between the lesser trochanter and 

the linea aspera. 

Actions: Adduction and flexion of the thigh. 

Nerve supply: Femoral and obturator nerves. 

• Adductor longus 

Origin: From the front of the pubis just below the pubic tubercle. 
Insertion: To the middle third of the linea aspera. 
Action: Adduction of the thigh. 
Nerve supply: Obturator nerve. 

• Adductor brevis 

Origin: From the inferior ramus of the pubis. 
Insertion: To the upper part of the linea aspera. 
Action: Adduction of the thigh. 
Nerve supply: Obturator nerve. 

• Adductor magnus 

Origin: From the inferior ramus of the pubis and the ramus of the 
ischium, back as far as the ischial tuberosity. 

Insertion: To the whole length of the linea aspera and to the adductor 
tubercle of the femur. 

Actions: Adduction and extension of the thigh (the latter action is car- 
ried out by the 'hamstring' part of the muscle which arises from the 
ischial tuberosity). 

Nerve supply: Adductor part by the femoral nerve and hamstring part 
by the sciatic nerve. 

• Gracilis 

Origin: From the inferior ramus of the pubis and the ramus of the 

ischium. 

Insertion: To the medial side of the tibia between sartorius and 

semitendinosus. 

Action: Adduction of the thigh. 

Nerve supply: Obturator nerve. 

• Biceps femoris 

Origin: Long head from the ischial tuberosity and short head from the 

linea aspera. 

Insertion: By a thick tendon into the head of the fibula. 

Actions: Extension of the hip and flexion of the knee. 

Nerve supply: Sciatic nerve (both components). 

• Semitendinosus 

Origin: From the ischial tuberosity. 

Insertion: To the medial side of the front of the tibia, behind sartorius 

and gracilis. 

Actions: Extension of the hip and flexion of the knee joint. 



Muscle index 165 



Nerve supply: Sciatic nerve (tibial component). 

• Semimembranosus 

Origin: From thie ischial tuberosity. 
Insertion: To a groove on the tibial medial condyle. 
Actions: Extension of the hip and flexion of the knee. 
Nerve supply: Sciatic nerve (tibial component). 

• Tibialis anterior 

Origin: From the lateral surface of the tibia. 

Insertion: To the base of the 1st metatarsal and the medial cuneiform. 

Actions: Dorsiflexion and inversion of the foot. 

Nerve supply: Deep peroneal nerve. 

• Extensor hallucis longus 

Origin: From the middle third of the shaft of the fibula. 
Insertion: To the base of the distal phalanx of the big toe. 
Actions: Extension of the big toe and dorsiflexion of the foot. 
Nerve supply: Deep peroneal nerve. 

• Extensor digitorum longus 
Origin: From the shaft of the fibula. 

Insertion: To the bases of the middle and distal phalanges of the four 

lateral toes via the dorsal extensor expansions. 

Actions: Extension of the toes and dorsiflexion of the foot. 

Nerve supply: Deep peroneal nerve. 

• Peroneus tertius 

Origin: Formed by the lower part of extensor digitorum longus. 
Insertion: Into the base of the 5th metatarsal. 
Ac?io«.- Dorsiflexion of the foot. 
Nerve supply: Deep peroneal nerve. 

• Extensor digitorum brevis 

Origin: From the upper surface of the calcaneus. 

Insertion: To the proximal phalanx of the big toe and to the extensor 

digitorum longus tendons of the next three toes. 

Actions : Dorsiflexion of the foot and extension of the toes. 

Nerve supply: Deep peroneal nerve. 

• Peroneus longus 

Origin: From the upper two-thirds of the lateral surface of the shaft of 

the fibula. 

Insertion: To the base of the 1st metatarsal and the medial cuneiform, 

via the groove on the cuboid. 

Action: Eversion of the foot. 

Nerve supply: Superficial peroneal nerve. 

• Peroneus brevis 

Origin: From the lower two-thirds of the shaft of the fibula. 

Insertion: To the base of the 5th metatarsal. 

Action: Eversion of the foot. 

Nerve supply: Superficial peroneal nerve. 

• Gastrocnemius 

Origin: From the femur just above both femoral condyles. 

Insertion: To the middle third of the back of the calcaneus via the tendo 

calcaneus. 

Actions: Plantar flexion of the foot; weak flexion of the knee. 

Nerve supply: Tibial nerve. 

• Soleus 

Origin: From the soleal line of the tibia and the upper part of the back of 

the fibula. 

Insertion: To the middle third of the back of the calcaneus via the tendo 

calcaneus in common with the gastrocnemius. 

Actions: Plantar flexion of the foot. Is the main factor in the ' muscle pump ' . 

Nerve supply: Tibial nerve. 

• Plantaris 



A detached piece of the lateral head of gastrocnemius with similar 
properties. 

• Popliteus 

Origin: From the back of the tibia above the soleal line. 

Insertion: To the lateral condyle of the femur. 

Actions: Flexion and medial rotation of the leg (thus 'unlocking' the 

extended knee joint). 

Nerve supply: Tibial nerve. 

• Tibialis posterior 

Origin: From the back of the tibia and fibula. 

Insertion: To the tuberosity of the navicular and other tarsal bones. 

Actions: Plantar flexion and inversion of the foot. 

Nerve supply: Tibial nerve. 

• Flexor hallucis longus 
Origin: From the back of the fibula. 

Insertion: To the base of the distal phalanx of the big toe. 
Action: Flexion of the big toe. 
Nerve supply: Tibial nerve. 

• Flexor digitorum longus 
Origin: From the back of the tibia. 

Insertion: To the bases of the distal phalanges of the four lateral toes via 
the openings in the tendons of flexor digitorum brevis. 
Action: Flexion of the toes. 
Nerve supply: Tibial nerve. 

• Abductor hallucis 

Origin: From the calcaneal tuberosity. 

Insertion: To the medial side of the proximal phalanx of the big toe. 

Action: Abduction of the big toe. 

Nerve supply: Medial plantar nerve. 

• Flexor digitorum brevis 
Origin: From the calcaneal tuberosity. 

Insertion: To the sides of the middle phalanges of the lateral four toes, 
its tendons being perforated by those of flexor digitorum longus. 
Action: Flexion of the toes. 
Nerve supply: Medial plantar nerve. 

• Abductor digiti minimi 

Origin: From the calcaneal tuberosity. 
Insertion: To the proximal phalanx of the little toe. 
Actions: Flexion and abduction of the little toe. 
Nerve supply: Lateral plantar nerve. 

• Lumbricals 

Origin: From the tendons of flexor digitorum longus. 

Insertion: To the dorsal extensor expansions. 

Actions: Assist the actions of the interossei. 

Nerve supply: First lumbrical by the medial and the others by the lateral 

plantar nerves. 

• Flexor digitorum accessorius 

Origin: From the undersurface of the calcaneus. 

Insertion: Into the side of the tendon of flexor digitorum longus. 

Action: Tenses the tendon of this muscle. 

Nerve supply: Lateral plantar nerve. 

• Flexor hallucis brevis 

Origin: From the underside of the cuboid. 

Insertion: To the sides of the proximal phalanx of the big toe with a 

sesamoid bone in each tendon. 

Action: Flexion of the proximal phalanx of the big toe. 

Nerve supply: Medial plantar nerve. 

• Adductor hallucis 

Origin: From the heads and from the bases of the metatarsals. 



166 Muscle index 



Insertion: Into the lateral side of the proximal phalanx of the big toe. 
Action: Adduction of the big toe. 
Nerve supply: Lateral plantar nerve. 

• Flexor digit! minimi brevis 

Origin: From the base of the 5th metatarsal. 
Insertion: Into the proximal phalanx of the little toe. 
Action: Flexion of the little toe. 
Nerve supply: Lateral plantar nerve. 

• Interossei: 

• Dorsal 

Origin: From adjacent sides of the metatarsals. 

Insertion: Into the dorsal extensor expansions and the sides of the 

proximal phalanges. 

Actions: Abduction of the toes; flexion of the metatarsophalangeal 

joints and extension of the interphalangeal joints. 

Nerve supply: Lateral plantar nerve. 

• Plantar 

Origin: From the bases of three of the metatarsals. 

Insertion: Into the dorsal extensor expansions and the sides of the 

proximal phalanges. 

Actions: Adduction of the toes and assisting the other actions of the 

dorsal interossei. 

Nerve supply: Lateral plantar nerve. 

The head and neck 

The muscles of mastication 

• Temporalis 

Origin: From the lateral side of the skull below the temporal line. 
Insertion: To the coronoid process of the mandible, extending down the 
anterior border as far as the third molar tooth. It passes deep to the 
zygomatic arch. 

Actions: Closes the mouth and clenches the teeth. The posterior fibres 
are horizontal and help to retract the mandible when closing the mouth. 

• Masseter 

Origin: From the lower border of the zygomatic arch. 

Insertion: To the lateral side of the mandible in the region of the angle. 

Actions: Closes the mouth and clenches the teeth. 

• Lateral pterygoid 

Origin: From the lateral pterygoid plate. 

Insertion: To the neck of the mandible and the intra-articular disc of the 

temporomandibular joint. 

Actions: It protrudes the mandible and moves the head of the mandible 

onto the articular eminence when the mouth is opened. 

• Medial pterygoid 

Origin: From the lateral pterygoid plate. 

Insertion: To the medial surface of the mandible near the angle. 

Action: Helps to close the mouth. 

Nerve supply of the muscles of mastication: The muscles of mastication 

are all supplied by the mandibular division of the trigeminal nerve. 

The muscles of facial expression 

The principal muscles of facial expression are shown in Fig. 67.1, from 
which their actions can be deduced. Only a few of them will be 
described here. 

• Occipitofrontalis 

Origin: The, frontal belly extends backwards from the forehead region 
and the occipital belly extends forwards from the occipital bone. 
Insertion: Both parts are inserted into the galea aponeurotica (epicra- 
nial aponeurosis). 



Actions: The frontal belly lifts the eyebrows when looking upwards and 
both bellies can move the whole scalp on the underlying loose fascia. 

• Orbicularis oculi 

In two parts. The orbital part surrounds the whole eye, blending with 
the frontal belly of occipitofrontalis. It closes the eye tightly. The 
palpebral part is in the eyelid and closes the eye gently as in sleep. 

• Orbicularis oris 

Surrounds the whole mouth and blends in with the surrounding muscles 
that are shown in Fig. 67. 1 . Closes the mouth and protrudes the lips. 

• Buccinator 

Origin: From the pterygomandibular ligament, where it is continuous 
with the superior constrictor of the pharynx. 

Insertion: Blends in with the orbicularis oris. Tightens the cheeks and 
keeps them in contact with the gums, thus preventing food collecting in 
the vestibule of the mouth. 

• Platysma 

Origin: From the skin over the upper part of the chest, crossing the 
mandible to blend in with the orbicularis oris. Pulls down the corners of 
the mouth and has an antisphincteric action on the neck as in loosening 
a tight collar. 

Nerve supply of the muscles of facial expression: All the muscles of 
facial expression are supplied by the facial nerve. 

• Trapezius 

Origin: From the superior nuchal line, the ligamentum nuchae and the 

spines of all the thoracic vertebrae. 

Insertion: Into the spine of the scapula, the lateral edge of the acromion 

and the lateral third of the clavicle. 

Actions: Extends the head on looking upwards, raises the tips of the 

shoulders, braces the shoulders back, and helps serratus anterior to 

rotate the scapula during abduction of the arm. 

Nerve supply: Spinal accessory nerve. 

• Sternocleidomastoid 

Origin: From the front of the manubrium (by a narrow rounded tendon) 

and the medial third of the clavicle. 

Insertion: To the mastoid process and the lateral part of the superior 

nuchal line. 

Actions: Rotates the head to the opposite side and flexes the cervical 

spine to the same side, thus bringing the ear nearer to the shoulder of the 

same side. Both muscles acting together can flex the cervical spine 

against resistance. An accessory muscle of respiration. 

Nerve supply: Spinal accessory nerve. 

• Scalenus anterior 

Origin: From anterior tubercles of the transverse processes of several 

cervical vertebrae. 

Insertion: To the scalene tubercle on the medial border of the 1 st rib, by 

means of a narrow pointed tendon. 

Actions: Flexes the cervical spine, produces lateral flexion to the 

same side and rotation to the opposite side. An accessory muscle of 

respiration. 

Nerve supply: Cervical spinal nerves. 

• Scalenus medius 

Origin: From the posterior tubercles of the transverse processes of 

most of the cervical vertebrae. 

Insertion: Into a large area on the 1st rib behind scalenus anterior. 

Actions: Similar to those of scalenus anterior. 

Nerve supply: Cervical spinal nerves. 

• Other muscles 

Other muscles of the neck, such as the strap muscles, are described 
fully in the text. 



Muscle index 167 



Index 



The index is arranged in word-by- word sequence; page numbers in italics refer to figures. 



abdomen 

arteries, 31-3 

lymphatics, 34-5 

muscles, 162 

nerves, 50—1 

surface anatomy, 52-3 

veins, 34-5 
abdominal 

aorta, J7.32 

oesophagus, 39 

viscera, surface markings, 53 
abdominal wall, 28-30 

lymphatic drainage, 30, 35 

surface markings, 53 
abducent nerve. 726,131,155 
abductor 

digit! minimi, 89,117,166 

hallucis, 117,166 

poUicis, 89 

poUicis brevis, 89,164 

pollicis longus, 164 
accessory 

duct(of Santorini), 47 

hemiazygos vein, 13 

muscles of respiration, 1 7 

nerve, 730,131 
cranial root, 121 
spinal root, 137, 145 
acetabular notch, 1 02 
acetabulum, 93,702 
Achilles tendon. 113,115,119 
acromioclavicular joint, 62,75 
acromion process, 91 
action potential, heart, 22 
acute cholecystitis, 45 
acute pancreatitis, 47 
adductor 

brevis, 108, 165 

canal, 95,707,108 

digiti minimi, 164 

hallucis, 166-7 

longus, 108,165 

magnus, 108, 165 

muscles, 105,706 

pollicis, 164 

tubercle, 93. 119 
adenocarcinomas, oesophagus, 11 
adenoid. 139,147 
aditus {middle ear), 157 
adrenal glands, 49 
airways, 14-15 
Alcock's canal, 59 
ampulla 

of rectum. 43 

ofVater, 47 
anal 

canal, 43,59 

sphincter, 42, 59 
anastomoses, porto-systemic, 34. 35 
anatomical snuffbox, 65.67,86,87,90,91 
anatomical spaces, 75 
anconeus, 83 
angina, 23 
angiograms 

carotid, 732 

vertebral, li4 
angioplasty, 23 
angle of Louis, 27 
angular incisure, 39 
anhidrosis, 121 
ankle, 92,114-17,77.5 

joint, 774.115 

surface anatomy, 119 



annular ligament, 83 
annulus fibrosus, 1 59 
anorectal ring, 59 
ansa cervicalis, 131 
anterior 

abdominal wall. 30,37.162 

cerebral artery, 1 33 

chest wall, 9 

clinoid processes, 123 

cranial fossae, 123 

cruciate ligament. 111 

cutaneous nerve, 127 

gluteal line, 55 

inferior cerebellar artery, 135 

inferior iliac spine, 102 

intercostal artery. 9 

intercostal spaces, 9 

intercostal veins, 9 

interosseous artery, 67 

interosseous branch, 71,85 

jugular vein, 135 

longitudinal ligaments, 159 

mediastinum, 1 1 

notch (spleen), 53 

pillars of the fauces, 146 

rectus sheath, 162 

sacral foramina. 55 

sacro-iliac ligament, 55 

shoulder dislocation, 79 

spinal artery, 135,161 

superior dental nerve, 1 29 

superior iliac spine, 55, 1 19 

thorax, 27 

tibial artery, 95 

venae comitantes, 97,113 

triangle of neck, 1 36 -7 

trunk, branches, 57 

tubercle, 159 

wrist, 91 
aorta. 9,53 
aortic 

arch, 13,135,141 

valve. 20,27 
apical lymph nodes, 69 
aponeurosis, 90.151 
appendicectomy, 43 
appendices epiploicae, 43 
appendicitis, 43 
appendix, 42,43 

blood supply, 32 

epididymis, 59 

testis, 59 
aqueous humour, 155 
arachnoid 

mater, 152, 160 

villi, 752, 153 
arcuate 

branch. 49 

ligaments, 9 
areola, 69 
areolar tissue, 151 
arm, 80-1 

sec also forearm 
arteria pancreatica magna, 47 
arterial reconstruction, 95 
arteries, 132—5 

abdomen, 31-3 

abdominal wall, 29, 30 

epigastric, 30 

foot, 117 

forearm, 85 

leg, 113 

lower limb, 94—5 



neck, 141 

orbit, 754 

pelvis, 57 

thigh, 107, 108 

upper limb, 66-7 
articular 

eminence, 125 

facets, 755, 159 
aryepiglottic muscle, 139 
arytenoid cartilages, 139 
ascending aorta, 13 
atheroma. 95 
atlas, 755, 159 
atrioventricular 

bundle. 23 

node, 23 
attic, 157 

atypical synovial joint. 75 
auditory nerve, 131, 157 
auricular surface of the ilium. 55 
auriculotemporal nerve, 129 
auriscope, 756,157 
auscultation, valvular, 27 
autodigestion, 47 
autonomic nervous system. 120-1 
avascular necrosis, 65, 105 
axilla, 65,69.75.76-7,90,91 
axillary 

artery, 67,76,77,135 

clearance, 77 

lymph nodes, 69,77 

nerve, 71,79,91 

tail, 69 

vein, 67,69,77 
axons, 127 
azygos vein, 13, 17 

back, muscles, 74 
Bartholin's glands, 59 
base (skull), 123,124-5 
basilar artery, 135 
basilic vein. 69, 81 
basivertebral veins, 159 
biceps, 73,81,83 

brachii, 163 

femoris, 108,165 

tendon, 64,90 
bifid spines, 159 
bifurcate ligament, 1 1 7 
Bigelow's ligament, 102 
bile 

canaliculi. 44 

ducts, 44 
biliary 

colic, 45 

system, 46 

tree, 44-5 
bladder, 53.60-1 
blindness, 133 
blood vessels, arm, 80 
bloodless fold of Treves. 43 
body of the sphenoid, 1 23 
brachial 

artery, 67,69,81,90,91 

plexus, 6,7,70,71 
branches, 71,73, 137 
injuries, 71,73 
trunks, 141,157 
brachialis, 71,73,81,83, 163 
brachiocephalic 

artery, 13, 135, 141 

vein, 13,135,141 
brachioradialis, 71.85.163 



168 Index 



breast, 91 

cancer, 77 

carcinomas, 69 

lymphatic drainage, 68-9 

surface markings, 27 

venous drainage, 68-9 
broad ligament, 56,57,61 
bronchi, 74,15.142 
bronchial 

arteries, 13, 17 

carcinomas, 15 

veins, 17 
bronchopulmonary segments, 15, 16 
buccalnerve, 129,131 
buccinator, 148, 167 
bulbospongiosus, 59 
bundle of His, 23 

caecum, 43 

calcaneocuboid joint, 115 
calcaneus, 114, 115, 119 
calf, 97 

muscles, 1 12. 1 13 
Camper's fascia, 30 
canal of Schlemm, 155 
canine teeth. 147 
canthus, 150 

capsular ligaments, 82. 109,159 
capsule (eyeball), 155 
carcinomas 

breast, 69 

bronchial, 15 

larynx, 139 

oesophagus, 1 1 
cardiac 

orifice, 39 

plexus, 25 

tamponade, 19 

veins, 24,25 
cardinal ligaments, 57 
cardiomegaly, 17 
carotid 

body, 133 

canal. 124 

sheath, 137,142 

sinus, 133 

triangle, 137 
carpal tunnel. 65,86-7 

syndrome, 71, 87 
carpometacarpal joints, 87 
carrying angle, 63 
Cauda equina, 160 
cave of Retzius. 61 
cavernous sinus, 127,135.752,153 
cavum trigeminale, 1 53 
central 

mass (sacrum), 55 

retinal artery, 133, 155 

tendon. 9 
centrilobular veins, 44 
cephalic vein, 69,75 
cerebrospinal fluid, 152, 155 
cervical 

cardiac branches, 121 

nerve, 127,131,149 

rib, 6,7 

spine, 159 

sympathetic chain, 73 

vertebrae, 137,755,159 
cervix, 61 

chemoreceptors. 1 33 
chest wall, 9.69 

muscles, 75 
chest X-ray (CXR), 76,17 
cholangitis, 45 
cholelithiasis, 45 
cholesterol stones. 45 

chorda tympani. 725, 129, 131, 145, 147, 157 
choroid, 155 
ciliary 

body, 155 

ganglion, 127, 155 

muscle, 121, 155 

processes, 155 



Circle of Willis, 133 
circumflex scapular artery, 67 
cisternachyli. 11,35 
clavicle, 62,91, 137 
clavipectoral fascia. 75 
clitoris, 59 
coccygeus, 55 
coccyx. 55 
cochlea, 157 
cochlear nerve, 131 
coeliac 

ganglion, 51, 121 

trunk, 32,33 
colic arteries, 33 
collateral ligaments, 83. 1 15 
Colles' fascia, 30 
Colles' fracture. 64 
colon. 43 
common 

carotid artery, 133,157 

extensor origin, 85 

flexor origin, 85 

iliac arteries, 57 

interosseous artery, 67 

palmar digital arteries, 67 

peroneal nerve, 92,700,101,111,119 
compartment syndrome, 113 
condyloid synovial joints, 87 
coneof light. 756,157 
conjoint tendon, 1 62 
conjunctiva, 150 
conjunctival 

fornix. 150 

haemorrhage, 150 
conoid 

ligament, 62 

tubercle, 62 
constrictor pupillae. 121 
coracoacromial ligament, 79 
coracobrachialis, 79,81,163 
coracoclavicular ligaments, 62,75 
coracohumeral ligament, 79 
coracoid process, 91 
cornea, 1 55 
coronary 

arteries, 22, 23 

bypass grafting, 23 
surgery, 97 

ligament, 36, 37 
corpus 

cavernosum, 59 

spongiosum, 59 
cortical radial branch, 49 
costal 

cartilages, 7 

margin, 27,45,53 
costocervical trunk, 13,135,141 
costochondral joint, 7 
costoclavicular ligaments, 62,75 
costophrenic angle, 17 
costotransverse joint, 7 
costovertebral joint, 7 
Cowper's glands, 59 
coxa 

valga, 93 

vara, 93 
cranial 

cavity, 152-3 

nerves, 126-7,130-1,744,145 

outflow, 121 

root, 131 
cranium, 123 
cribriform 

fascia, 106, 107 

plate of ethmoid, 123 
cricoid cartilage, 139,157 
cricothyroid 

joint. 139 

ligament, 139 

muscle, 138,139 
cricovocal membrane, 7iS, 139 
cruciate 

anastomosis, 95 

ligaments. 770, 111 



cubital fossa, 82-3 
cuboid bone, 115 
cuneiform bone, 1 15 
cutaneous nerves, 65,127,137 
CXR (chest X-ray), 76,17 

dartos, 59 

deciduous teeth, 147 
deep 

circumflex iliac artery, 30 

external pudendal artery, 107 

fascia of neck, 137 

flexor muscles, 1 13 

inguinal ring, 53.775 

palmar arch, 67,91 

palmar branch, 67 

perineal pouch, 59 

peroneal nerve, 101,113 

plantar arch, 95, 117 

temporal arteries. 133 

temporal nerves, 129 

terminal branch, 73 

transverse metacarpal ligaments, 1 17 

transverse metatarsal ligaments, 1 17 

veins, 69,97 

venous thrombosis, 97, 113 
deltoid, 71,75,79.115,163 

injuries, 73 
deltopectoral triangle, 75,91 
demifacets, 159 
Denonvilliers' fascia, 43,61 
dens, 755,159 
dentate line, 43 
dermatomes, 760, 161 
descendens 

cervicalis, 127. 131 

hypoglossi, 127, 131, 145 
descending thoracic aorta, 72, 13 
detrusor, 61 
diaphragm, 5,9,162 

chest X-rays, 17 

surface markings, 27 
diaphragmaselli, 153 
digastric 

muscle, 145 

triangle, 137 
dilator pupillae, 155 
diploe, 123 
diploic veins, 123 
direct inguinal hernia. 53 
distal transverse crease, 91 
dorsal 

carpal arch. 67 

carpal branch, 67 

cutaneous branch, 73 

interosseous muscle, 55,89,95, 117, 167 

lingual arteries, 133 

metatarsal branch, 95 

scapular artery, 13,135,141 

tubercle (of Lister). 64,91 

venous arch, 1 19 

venous network, 69, 9 1 
dorsalis 

pedis artery, 95, 1 13 

pedis pulse, 1 19 
dorsiflexor muscles, 772 
ductus deferens see vas deferens 
duodenal ulcer, perforated, 25 
duodenum, 39 

blood supply, 39 
dura mater, 160 

fibrous layer, 152 

serous layer, 152 
dural venous sinuses. 135, 152 
DVT(deep venous thrombosis), 97, 113 

ear, 156-7 

ED (extensor digitorum), 89. 119, 164 

efferent ducts, 59 

ejaculatory ducts, 61 

elbow, 91 

joint, 82-3 
electrocardiograms, 22 
embryonic pharynx, 142 



Index 169 



emissary 

foramina, 123 

veins, 123.135,151 
empyema, 1 5 
endometrium, 61 
endopelvic fascia. 57 
epidymis, 58, 59 
epigastric arteries, 30 
epiglottis. 139 
epitympanic recess, 157 
Erb-Duchenne paralysis, 73,161 
ethmoid, 125 
ethmoidal 

nerves, 129 

sinuses, 147 
Eustachian tube, 139, 157 
expiration, mechanisms, 17 
extensor 

carpi radialis brevis, 87,163-4 

carpi radialis longus, 85, 87, 163-4 

carpi ulnaris, 164 

digiti minimi, 164 

digitorum. 89, 119. 164 

digitorum brevis, 113, 166 

digitorum longus, 113,115,166 

hallucis longus, 113,115,119,166 

indicis, 164 

muscles, 81,i72 

poUicis brevis. 83,164 

pollicis longus, 83,164 
external 

anal sphincter. 59 

auditory meatus, 124 

carotid artery, 132, 133, 145, 149 

iliac artery, 57. 95 

intercostal muscles, 9 

jugularvein, 135,137,157 

laryngeal nerve. 131, 139 

oblique muscles. 2-5,30,162 

urethral meatus, 59 
extrinsic muscle (tongue), 144 
eye, 129. 148, 150 

anterior chamber, 155 

posterior chamber, 155 
eyeball. 154-5 

face, 123,148-50 

bones, 1 25 

nerves, 126, 149 
facial 

artery, 133,145,150,157 

muscles, 148 

nerve, 121,730,131,149.157 

vein, 135, 150 
facial expression, muscles, 148, 167 
falciform 

ligament, 36, 37, 45 

margin, 106 
fallopian tubes, 61 
false 

cords, 139 

pelvis, 55 

ribs, 7 
falx 

cerebelli, 153 

cerebri. 152,153 
fascia 

of Denonvilliers, 43,61 

lata, 106 
fasciotomy, 113 

FDP (flexor digitorum profundus), 85,87,89, 163 
EDS (flexor digitorum superficialis), 85,87,89, 163 
femoral 

artery, 94.95.107 

canal, 107,119 

condyles, 93, 119 

head. 93, 103 

hernia, 118 

neck, 93, 103 
fractures. 105 

nerve, 51,95,99,107 

pulse, 119 

shaft, 93 

sheath, 107 



triangle, 95,706,107 

vein, 97,106,107 
femur, 92,93,110 
fibrocartilage, 75 
fibrous flexor sheaths, 89 
fibula, 92,93,114 
fibular 

head. 93,119 

neck. 93 

notch, 93 
fight or flight reaction, 1 2 1 
Filaria bancrofti , 97 
filiform papillae, 147 
filum terminale, 160 
fingers, movements, 89 
flexor 

carpi radialis, 87,163 

carpi ulnaris, 85, 87, 163 

digiti minimi, 89,164 

digiti minimi brevis, 117,167 

digitorum accessorius, 1 17, 166 

digitorum brevis, 117, 1 66 

digitorum longus, 113,115,117, 119. 166 

digitorum profundus. 85,87,89,163 

digitorum superficialis, 85, 87, 89, 163 

hallucis brevis, 117,166 

hallucis longus, 113,115,117,119,166 

muscles, 81,83,113 

pollicis brevis. 89,164 

pollicis longus, 87,89, 163 

retinaculum, 65, 87 

tendons, synovial sheaths, 56,87 
foot, 772,114-17 

dorsum, 776, 117 

joints, 115 

movements, 113 

muscles, 776, 1 17 

sole. 776,117 

surface anatomy, 1 1 9 

tendons, 775 
foramen 

caecum (tongue), 143 

epiploic, 36, 37 

lacerum, 123,124 

magnum, 123,124,135 

ovale, 123, 124 

rotundum, 123 

spinosum, 123,124,125,145 

transversarium, 159 

ofWinslow, 37 
forearm. 84-5 

lateral cutaneous nerve, 71 
fourchette, 59 
fovea, 93,102 

EPL (flexor poUicis longus), 87, 89, 1 63 
frenulum of glans penis, 59 
frontal 

air sinuses, 123 

bone, 123,125 

nerve, 129, 149 

sinuses, 147 
fundus of uterus, 61 
fungiform papillae, 147 

gall-bladder, 44-5,53 

fossa, 45 
gallstones, 45,47 
ganglia, 121 
ganglion impar, 121 
gastric arteries, 37,33 
gastrocnemius, 113.115,166 
gastrosplenic ligament, 36, 37, 47 
gemellus 

inferior, 105 

superior, 105 
genicular 

artery, 95 

branches, 101 
geniculate ganglion, 1 3 1 
genioglossus muscle, 147 
geniohyoid muscle, 145 
genitofemoral nerve, 51,107 
genuof the corpus callosum, 133 
glans penis, 59 



glaucoma, 155 
glenohumeral 

joint, 78-9 

ligaments, 79 
glenoid 

cavity, 78 

fossa, 63 

labrum, 79 
glossopharyngeal nerve, 121, 131, 145, 146, 

147 
glottis, 139 
gluteal 

fold, 105 

surface (ilium). 55 
gluteal region. 105 

deep structures, 104 

superficial muscles, 103 

surface anatomy, 1 1 9 
gluteus 

maximus. 105, 164 

medius, 105, 164-5 

minimus, 165 
gonadal arteries, 33 
gracilis, 108,165 
great 

saphenous vein, 97,106,107,119 

vessels. 18 

surface markings, 27 
greater 

auricular nerve, 127,137 

occipital nerve, 1 27 

palatine foramen, 125 

palatine nerves, 129 

petrosal branch, 131 

sciatic foramina, 55 

sciatic notch. 55 

trochanter, 93, 119 

tubercle (humerus), 63 

wings of sphenoid. 1 23 
groin, lymph nodes, 97 

haematuria, 49 
haemopericardium, 19 
haemorrhage. 1 1 
hamstrings, 105, 108 
hand, 65,88-9,91 

'clawed', 73 

nerves, 72-3,55 
hard palate, 146 
haustra. 43 
head 

injuries, 133 

lymphatics, 156-7 

muscles, 167 

surface anatomy, 156-7 
heart. 18-23 

borders, 17 

surface markings, 26 

surfaces, 19 
heel, 119 

hemiazygos vein, 13, 17 
hepatic 

arteries, 31, 33,45 

veins, 45 
hernia, 52 
hip 

bone, 54,55 

joint, 93,102-5 

surface anatomy, 1 1 9 
hook of the hamate, 9 1 
Horner's syndrome, 73,121 
humeral 

capitulum, 63. 83 

head. 63,79 

shaft, fracture, 71 
humerus, 63, 91 

anatomical neck. 63 

surgical neck, 63 
Hunter's canal, 95,707,108 
hyaline cartilage. 79 
hydatid of Morgagni, 59 
hydronephrosis, 49 
hyoglossus muscle, 145, 147 
hyoidbone, 139,157 



170 Index 



hypercalcaemia, 49 
hyperhidrosis, 25 
hypogastric plexuses, 121 
hypoglossal 

canal. 123, 124 

nerve, 131,133.145 
hypothenar muscles, 89 

ileal branches, 33 
ileocaecal fold, 43 
ileocolic artery, 31 , 33 
ileum. 40.41 
iliac 

crest, 55 

fossa, 55 
iliacus, 706, 107, 165 
iliococcygeus, 55 
iliofemoral ligament, 102 
iliohypogastric nerve, 51 
ilioinguinal nerve, 51 
iliolumbar artery, 57 
iliopectineal line, 55 
iliotibial tract. 106,705 
ilium, 55 

incisive fossa, foramina, 1 25 
incisors, 147 
incisura angularis, 39 
incus, 157 

indirect inguinal hernia, 53 
inferior 

alveolar artery, 133 

alveolar nerve, 1 29 

cardiac branch. 131 

cervical ganglion, 121, 141 

colliculus. 127 

concha, 125 

constrictor, 139 

deep cervical lymph nodes. 69, 157 

epigastric artery, 53,775 

extensor retinaculum, 1 13 

gluteal artery, 57,95,105 

gluteal line. 55 

gluteal nerve, 101, 105 

hypogastric plexus, 51 

labial branch, 133 

mediastinum, 1 1 

mesenteric artery, 32,33 

oblique muscle, 155 

ophthalmic vein, 155 

orbital fissure, 155 

parathyroid gland, 143 

peroneal retinaculum, 1 1 3 

petrosal sinus, 135 

pubic ramus, 55 

rectal branches, 59 

rectus muscle, 155 

sagittal sinus, 135,153 

thyroid artery, 7J2,141,142 

thyroidvein, 135,142 

tibiofibular joint, 93,113 

ulnar collateral branch, 67 

vena cava, 9,34,35.44.45,49 

vesica! artery, 57,61 
infraclavicular lymph nodes, 69. 75 
infrahyoid 

lymph nodes, 157 

muscles, 131, 142 
infraorbital 

foramen, 125 

nerve, 129, 157 
infraspinatus. 75,79,163 
infratemporal region, 145 
infratrochlear nerve, 129 
inguinal 

canal, 29,30,52,162 

hernia, 53,775 

ligament, 53,95.107,162 
inner ear, 157 
innermost intercostals, 9 
insect bites, 69 
inspiration, mechanisms, 17 
interarytenoid muscles, 139 
intercavernous sinuses, 135 
interchondral joint, 7 



intercondylar 

area, 93 

eminence, 93 

notch, 93 
intercostal 

artery, 161 

nerves, 9 

space, 5, 9 
intercostales intimi, 9 
interlobar branch, 49 
intermediate cutaneous nerve, 99 
intermittent claudication. 95 
internal 

anal sphincter. 59 

auditory artery, 135 

auditory meatus, 123 

capsule. 133 

carotid artery, 132, 133. 145 

carotid nerve, 121 

carotid stenosis, 7J2 

iliac artery, 57 

intercostal muscle, 9 

jugularvein, 13,135,137.141,145 

laryngeal branch, 147 

laryngeal nerve, 131,139 

oblique muscles. 25,30,162 

pudendal artery, 57 

thoracic artery, 13,135,141 

urethral meatus, 61 
interosseous 

borders, 64 

membrane, 85,92,113 

muscles, 55,89.164,167 

sacro-iliac ligament, 55 

talocalcaneal ligament, 117 
interphalangeal joints. 73,87 
interspinous ligaments, 159 
intertransverse ligaments, 159 
intertubercular sulcus, 63 
interureteric ridge, 61 
intervertebral 

discs, 159 

joints, 159 
intestinal tumours, 45 
intra-abdominal branches, 99 
intracranial venous sinuses, 134 
intramuscular injections, 119 
intrinsic muscles of tongue, 1 47 
ipsilateral anhidrosis, 73 
iridocorneal angle, 155 
iris, 155 
ischaemia, 95 
ischaemic necrosis, 67 
ischial 

ramus, 55 

tuberosity, 55, 119 
ischiocavernosus, 59 
ischiofemoral ligament, 102 
ischiorectal fossae, 42,59 
ischium, 55 
I VC (inferior vena cava), 9, 34, 35,44, 45, 49 

jejunal branches, 33 
jejunum, 40 
jugular 

foramen, 123,124 

trunk, 157 
jugulo-omohyoid lymph nodes, 157 
jugulodi gastric lymph nodes, 157 

kidney, 45.49.53 
Klumpke's paralysis, 73 
knee, 92 

injuries. Ill 

joint, 109-11 

nerves, 101 

labia 

majora, 59 

minora, 59 
labrum acetabulare, 102 
lacrimal 

bone, 125 

gland, 121,129.150 

nerve, 129 



puncta, 150 

sac, 125,150 
lactiferous 

ducts, 68 

sinus, 69 
lacunae I at erales, 153 
laryngopharynx, 1 39 
laryngoscopy, 138. 139 
larynx. 137,138-9 

carcinomas, 139 

lymph drainage, 157 
lateral 

calcaneal branch, 95 

circumflex femoral artery, 95,99 

collateral ligament, 83,93,110, 115.119 

cricoarytenoid, 139 

cutaneous nerve, 7 1 , 99 
calf. 101 
thigh, 51 

epicondyle of humerus, 85.91 

femoral cutaneous nerve, 107 

head of triceps, 63 

intercondylar tubercles, 93 

ligament of foot, 117 

longitudinal arch of foot, 1 17 

malleolus. 93 

mass (sacrum), 55 

meniscus, 1 1 1 

pectoral nerve, 73,75 

plantar artery, 94,95,117 

plantar nerve, 700, 101, 117 

pterygoid muscle, 145,167 

pterygoid plate, 124 

rectus muscle, 155 

sacral artery, 57,161 

sulcus, 133 

supracondylar ridge, 85 

thoracic artery, 67 
latissimus dorsi, 75,79,162 

paralysis, 77 
left 

atrium, 20. 21 

common carotid artery, 13 

coronary artery. 13 

crus, 9 

phrenic nerve, 25 

recurrent laryngeal nerve, 25,142 

subclavian artery, 13 

vagus nerve, 24,25 

ventricle, 20,21 
leg, 112-13 
lens, 155 
lesser 

occipital nerve, 127, 137 

palatine foramen, 1 25 

palatine nerves, 129 

sciatic foramina, 55 

sciatic notch, 55 

trochanter, 93 

tubercle (humerus), 63 

tuberosity, 91 

wing of sphenoid, 123 
levator 

ani, 54,55 

palati, 146 

palpebrae superioris, 155 

prostatae, 55 

scapulae, 75. 162 
lienorenal ligament. 36,31,41 
ligamenta flava, 1 59 
ligamentum 

nuchae, 91 

patellae, 93,110, 119 

teres, i6, 37,45,93, 102, 103 

venosum. 45 
linea 

alba, 25,30,53,162 

aspera, 93 

semilunaris, 25,30,53 
lingual 

artery, 133.145 

nerve, 129, 145, 147 

tonsil, 147 

vein, 135 



Index 171 



lingular segment, 17 
liver, 44-5.53 

cirrhosis, 11 

hilum, 45 

lobules, 44.45 
lobar branch, 49 
long 

ciliary nerves, 129 

extensor tendons, 89 

flexor tendons, 89 

plantar ligament, 1 17 

thoracic nerve {of Bell), 73,77 
longitudinal arches of foot, 1 17 
lower 

deep cervical lymph nodes, 157 

gastrointestinal tract, 42-3 

subscapular nerve, 73 

ureter, 49 
lower limb 

arteries, 94—5 

leg, 112-13 

lymphatics, 96-7 

lymphoedema, 96,97 

muscles, 164-7 

nerves, 98-101 

osteology, 92-3 

surface anatomy, 118-19 

veins, 96—7 
lumbar 

artery, 161 

plexus, 50,51,99 

puncture, 159, 160 

spine, 159 

sympathectomy, 51 

sympathetic chain, 51 

vertebrae, 158, 159 
lumbosacral angle, 55 
lumbrical muscles, 71,89, 117,164, 

166 
lunate bone, 64 
lung, 16-17, 142 

collapse, 15 

hilum, 14, 15 

surface markings, 26, 27 
lymph, 69 

lower limb, 96 
lymph nodes, 35,65,69 

head and neck, 756 

lower limb, 97 
lymphadenopathy, 69 
lymphatics, 75 

abdomen, 34-5 

breast, 68 

chest, 9,10,11,68,69 

head, 156-7 

lower limb, 96—7 

neck. 156-7 

thigh, 107 

upper limb, 69 
lymphoedema 

lower limb, 96,91 

upper limb, 69 

McBurney's point, 52,53 
Mackenrodt's ligaments, 57 
macula lutea, 155 
malleus, 157 
mandible, i24. 125, 145 
mandibular 

division, 129 

foramen, 125 

fossa, 125 

nerve, 149 
manubriosternal joint, 7 
manubrium, 7 

marginal artery (of Drummond), 32, 33 
marginal mandibular nerve, 1 3 1 
masseter, 145,74(5, 167 
mastication, muscles, 148, 167 
mastoid 

air cells, 124,157 

antrum, 157 

process, 124 
maxilla, 125 



maxillary 

air sinus, 125 

artery, 133,145,149 

division, 129 

nerve, 133 

sinus, 147 
meatuses of nose, 147 
median cubital vein, 91 
medial 

circumflex femoral branch, 95 

collateral ligament, 83, 1 10, 1 15, 1 19 

crest, 93 

cutaneous branch, 99 

cutaneous nerve, 73 

epicondyle of humerus, 63,91 
fracture, 73 

head of gastrocnemius, 1 10 

head of triceps, 63 

intercondylar tubercles, 93 

ligament, 1 17 

longitudinal arch of foot, 117 

malleolus, 93, 119 

meniscus, 1 1 1 

pectoral nerve, 73 

plantar artery, 94,95,117 

plantar nerve, 700,101, 117 

pterygoid muscle, 145,167 

pterygoid plate, 124 

rectus muscle, 155 
median 

cubital vein, 69,52 

nerve, 70,71,81,85,55.90,91 

raphe (scrotum), 59 

umbilical ligament, 37,60 
mediastinal 

artery, 13 

structures, chest X-rays, 17 
mediastinum, 10-13,24 

middle. 19 
Meibomian glands, 1 50 
membranous 

labyrinth, 157 

urethra, 61 
meninges, 152, 159, 160 
meningococcus, 47 
meningocoele, 159 
menisci. 111, 119 
meniscofemoral ligaments. 111 
mental 

foramen, 125 

nerve, 129, 157 
meralgia paraesthetica, 99 
mesenteric artery. 32 
mesenteries, 36, 37 
mesocolons, 37 
metacarpals, 89 

metacarpophalangeal joints, 73,87 
metatarsals, 115, 119 
metopic suture, 123 
midcarpal joint, 87 
middle 

cerebral artery, 133 

cervical ganglion, 121,141 

constrictor, 139, 145 

cranial fossae, 123 

ear, 750,756,157 

mediastinum, 1 1 

meningeal artery, 123.133,145,157 

rectal artery, 57 

superior dental nerve, 1 29 

thyroid vein, 135,142 
mi dtarsal joint, 115 
milk teeth, 147 
mitral (bicuspid) valve, 20,21 
molars, 147 
mons pubis, 59 
Montgomery's glands, 69 
mouth, 145. 146-7 
mucous membranes, 15, 139 
muscles 

abdomen, 162 

abdominal wall, 30 

calf, 772,113 

chest wall, 75 



eyeball, 155 
foot, 776,117 

forearm, 54,85 

head, 167 

leg, 113 

lower limb, 164-7 

neck, 167 

nerves, 101 

pectoral region, 74 

scapular region, 74 

thigh, 706 

upper limb, 74,75. 162-4 

triangle, 137 
musculocutaneous nerve, 71,81 
mylohyoid 

muscle, 145 

nerve, 129 
myocardial infarction, 23 
myometrium, 61 
myosis, 121 
myotomes, 161 

nasal 

bone, 125 

branch of facial artery, 1 33 

cavity, 125,746,147 

septum, 125, 147 
nasociliary nerve, 129 
nasolacrimal duct, 147,150 
nasopalatine nerves, 125 
nasopharynx, 139 
navicular bone of foot, 115, 119 
neck, 7J6, 137 

arteries, 141 

lymphatics, 1 56 -7 

muscles, 167 

nerves, 726, 141 

root, 140-1 

surface anatomy, 156-7 

upper, 144-5 

veins, 141 
nerves 

abdomen, 50-1 

arm, 50 

face, 726, 149 

foot, 117 

forearm, 85 

leg, 113 

lower limb, 98-101 

muscles, 101 

neck. 726,141 

orbit, 754 

palsies, 72 

thigh, 107,108 

thorax, 24-5 

upper limb, 70-3,91 
nose, 146-7 
nucleus pulposus, 159 
nutrient artery, 67,95 

oblique popliteal ligament, 1 1 
obturator 

artery, 57. 103 

externus, 108, 165 

fascia, 54 

foramen, 53, 99 

internus, 105, 165 
nerve, 101 

membrane. 55 

nerve, 51,95,99, 107 
occipital 

artery, 133 

bone, 123 

condyles, 124 
occipitofrontalis muscle, 151,167 
oculomotor nerve, 121,726,127, 

155 
odontoid process, 159 
oedema, 1 13 
oesophageal 

artery, 13 

varices, 1 1 
oesophagus. 9,70,11,137,142 

carcinomas, 11 



172 Index 



olecranon process, 91 
olfactory nerve, 123,127 
omenta, 36. 37, 39 
omohyoid muscle, 1 42 
ophthalmic 

artery, 123.133, 155 

division, 129 

veins, 135 
opponens 

digiti minimi, 89,164 

pollicis, 89,164 
optic 

canal, 123,754,155 

chiasma, 126, 127 

disc, 155 

nerve, 123, 127, 129 

tract, 127 
orbicularis 

oculi, 148, 167 

oris, 167 
orbit, 125.135,154-5 
orbital muscle, 148 
oropharynx. 139 

OS 

innominatum, 54,55 

trigonum, 115 
osseous labyrinth, 157 
ossicles, 157 
osteoarthritis, 65 
otic ganglion, 121, 145 
outer ear, 157 
oval window, 157 
ovarian ligament, 61 
ovary, 61 

palate, 146-7 
palatine 

bone, 125 

horizontal plate, 125.146 
perpendicular plate, 1 25 

process of maxilla, 125,146 
palatoglossal arch, 146 
palatoglossus muscle, 146 
palatopharyngeal arch. 146 
palatopharyngeus muscle, 146 
pahn(ofhand), 89 
palmar 

aponeurosis. 89 

carpal arch, 67 

carpal branch, 67 

cutaneous branch of median nerve, 7 1 

cutaneous branch of ulnar nerve, 73 

interosseous muscle, 88 

metacarpal arteries. 67 

skin, cutaneous supply, 71 
palmaris longus, 90,163 
palpebral muscle, 148 
pancreas, 46-7,53 
pancreatic duct {of Santorini), 39 
pancreatic duct{of Wirsung), 39.45, 

47 
pancreaticoduodenal artery, 31 , 33 
pancreatitis. 45,47 
paranasal sinuses, 147 
parasympathetic 

fibres, 126,128 

nervous system, 51,720,121,155 

outflow, 121 
parathyroid glands, 143 
paratonsillar vein, 147 
paratracheal lymph nodes . 157 
parietal bone, 123 
parotid 

duct, 149, 157 

gland, 121,130.149 
tumours, 149 
pars flaccida, 157 
patella, 93,110,119 

injuries, 93 
patellar retinacula, 110 
pectineus, 107, 165 
pectoral 

muscles, 90 

region, 74-5 



pectoralis 

major, 75.79.91,162 

minor. 67,75,162-3 
pudendal canal, 59 
pelvic 

arteries, 56 

brim, 55 

cavity. 55 
contents, 60 

fascia, 57 

floor, 54,55 

outlet, 55 

splanchnic nerves, 51,121 

tumours. 97 

viscera, 60-1 
pelvis, 50,54-7,60,105 

lymphatic drainage, 35 

sex differences, 55 
penile urethra, 61 
penis, 59 

peptic ulcer disease, 39 

percutaneous transluminal angioplasty (PTA), 95 
perforating 

arteries, 95 

cutaneous nerve, 101 

veins. 97 
pericardium, 18, 19 
pericranium, 151 
perineal 

body, 55 

membrane, 59 
perinephric fat, 49 
perineum. 58-9 
peripheral nerve, 161 
peripheral vascular disease, 51,95 
peritoneal cavity, 37 
peritoneum, 36-7 
permanent teeth, 147 
peroneal 

artery, 95, 113 

compartment, 113 

retinacula, 113 

tubercle, 115,119 
peroneus 

brevis. 113,119,166 

longus, 113,119,166 

tertius, 113, 166 
petrous temporal, 123 
phalanges, 1 15 
pharyngeal 

branch of vagus. 131, 146 

plexus, 146 

tonsil, 139, 147 

vein, 135 
pharyngotympanic tube, 139,157 
pharynx, 137,138-9,143,145,146 
phrenic nerve, 25,141 
pia mater, 152, 160 
piriformis muscle, 105,165 
pisiform bone, 91 
pivot joints, 83 
plantar 

aponeurosis, 1 17 

calcaneonavicular, 117 

interosseous, 167 

metatarsal branch, 95 
plantaris, 113, 166 
platysma, 148, 167 
pleura. 9, 14-15 

surface markings, 27 
pleural aspiration, 9 
pleural cavity, 15 

surface markings, 26 
pleurisy, 15 
pneumococcus, 47 
pneumonia, 15 
pneumothorax. 15 
popliteal 

artery, 95, 111 

fossa, 111,111 

lymph nodes, 111 

pulse, 119 

trifurcation, 95 

vein, 95,97,107,111 



popliteus, 93,110, 166 
porta hepatis, 45 
portal 

system, 44 

vein, 34,35,45 
posterior 

abdominal wall, 48-9 

cerebral artery. 133. 135 

chest wall, 9 

communicating artery, 133, 135 

cranial fossa, 123 

crico-arytenoid, 138, 139 

cruciate ligament, 1 1 1 

cutaneous nerve of thigh. 101, 105 

gluteal line. 55 

inferior cerebellar artery, 1 35 

intercostal artery. 9,13 

intercostal spaces. 9 

interosseous artery, 67 

interosseous branch. 85,91 

interosseous nerve, 71 

longitudinal ligaments, 159 

mediastinum, 1 1 

pillar of fauces, 146 

rami, 127 

sacro-iliac ligament, 55 

spinal artery, 135,161 

superior dental nerve, 129 

superior iliac spine, 55 

tibial artery, 95, 113 

venae comitantes, 97,119 

tibial pulse. 1 19 

triangle, 136—7 

trunk, branches, 57 

tubercle, 115.159 
postganglionic fibres, 120,121 
pouch of Douglas, 43 
preganglionic fibres, 120,121 
premolars, 147 
prepuce, 59 
presacral nerves, 51 
pretracheal fascia, 137,142 
prevertebral fascia, 137 
princeps pollicis. 67 
processus vaginalis. 53 
profunda 

brachii artery, 67,71,81 

femoris artery, 95,108 
promontory of tympanic cavity, 157 
pronation, mechanisms, 64 
pronator 

quadratus, 83, 163 

teres. 83, 163 
prostate, 60,61 
prostatic 

sinus, 61 

urethra, 61 

utricle, 61 
proximal 

phalanges, 89 

transverse crease, 91 
psoas. 106. 107 

bursa, 103 

major, 162, 165 
PTA (percutaneous transluminal angioplasty), 

95 
pterygoid plates of the sphenoid, 125 
pterygomandibular ligament, 139 
pterygomaxillary fissure. 125 
pterygopalatine fossa, 125, 129, 133, 145 
ptosis, 73, 121 
pubic 

arch, 55 

crest, 55 

tubercle, 53.55.775 
pubis, 55 

pubocervical ligaments, 57 
pubofemoral ligament. 102 
puboprostatic ligaments, 61 
puborectalis. 55 
pubovesical ligaments, 57,61 
pudendal 

canal, 59 

nerve, 101, 105 



Index 173 



pulmonary 

ligament, 15 

plexus, 17 

valve, 20,21 
pupil, 155 

pupillary constriction, 73 
pyloric sphincter, 38, 39 
pyramidalis, 30 
pyriform fossa, 139 

quadrangular space, 74, 75 
quadratus 

femoris. 105, 165 
nerve, 101, 105 

lumborum, 162 
quadriceps femoris, 93. 107,110, 165 

radial 

artery, 67.85.91 

collateral ligament, 87 

head, 63,64,91 

nerve, 63, 70, 71, 81, <54, 85,91 

tuberosity, 64 
radialis indicis, 67 
radiocarpal joint, 87 
radius, 64,91 
Raynaud's syndrome, 25 
recto-uterine pouch (of Douglas), 43, 61 
rectovesical fascia, 43, 6 1 
rectum, 42,43 
rectus 

abdominis, 25,30, 162 

femoris, 105, 165 

sheath, 25,30,162 
recurrent branch 

laryngeal nerve, 131, 139 

median nerve, 11,88 
red pulp, 47 
renal 

arteries, 32,33,49 

columns, 48 

cortex, 49 

fascia, 49 

medulla, 49 

pelvis, 49 

veins, 49 
respiration, mechanisms, 17 
rete testis, 59 
retina, 126, 127, 155 
retinaculaof hip joint, 102,105 
retrocalcaneal bursa, 113,115 
retromandibular vein, 135,149 
rhomboids, 162 

major, 75 

minor, 75 
ribs, 6,1,140 
ridge of Passavant, 146 
right 

atrium, 20, 21 

common carotid, 13 

coronary artery, 1 3 

crus of diaphragm, 9,10 

internal jugular vein, 1 35 

lymph duct, 70, 11, 135 

lymphatic trunks, 69 

phrenic nerve, 24, 25 

subclavian, 13 

transverse sinus, 1 35 

vagus nerve, 24,25 

ventricle, 21 
rotator cuff muscles, 63, 78, 79, 163 
round ligament, 57 
rugae of stomach, 39 

saccule of labyrinth, 157 
sacral 

canal, 55 

cornua, 55 

hiatus, 55 

outflow. 121 

plexus, 57,700,101 

promontory, 55 

vertebrae, 159 



sacro-iliac joint, 55 

sacrospinous ligament, 54,55.105 

sacrotuberous ligament. 54,55, 105 

sacrum, 54,55, 159 

salivary glands. 145 

saphenous 

nerve, 99 

opening, 106 
sartorius, 107, 165 

SBO (small bowel obstruction), 40,41 
scalene 

muscles, 140 

tubercle, 7 
scalenus 

anterior, 140, 167 

medius, 140, 167 
scalp, 151 

scaphoid bone. 64,65,91 
scapula, 27, 63, 91 
scapular 

anastomosis, 77 

inferior angle, 91 

region, 74-5 
Scarpa's fascia. 30 
Schmorl'snode, 159 
sciatic 

foramina, 105 

nerve, 700, 101,105, 107,118 
damage, 119 
sclera, 155 
scrotum, 53,59 
segmental 

arteries, 49 

bronchus, 16 
sella turcica, 123 
semicircular 

canals, 157 

ducts, 157 
semilunar cartilages, HI 
semimembranosus, 108, 166 

bursa, 110 
seminal vesicles, 61 
seminiferous tubules, 59 
semitendinosus, 108,165-6 
sensory 

fibres, 145 

nerves, 126 
serous dura. 752 
serratus anterior, 75,79,162 

paralysis, 77 
sex hormones, 61 
short plantar ligament, 1 17 
shoulder, 78-9 

dislocations, 71,78,79 
sigmoid 

branches, 32, 33 

sinus, 135 
sinu-atrial (SA) node, 22,23 
sinus 

oflarynx, 139 

venosus sclerae, 155 
skin 

abdominal wall, 30 

hand, 89 
skull, 122-5 
small 

bowel obstruction, 40,41 

intestine, 41 

mesentery of . i6, 37 

saphenous vein, 97,119 
soft palate, 146 
soleal 

line, 93 

plexus, 97 
soleus, 113,115,166 
spermatic cord, 29, 30, 53 
spermatogenesis, 59 
spheno-ethmoidal recess, 147 
sphenoid, 124 
sphenoidal 

air sinus, 123,135, 147 
sphenopalatine 

ganglion, 121, 129 

nerve, 129 



sphincter 

ofOddi, 39 

pupillae, 155 

urethrae, 61 

vaginae, 55 

vesicae, 61 
spina bifida, 159 
spinal 

arteries, 161 

cord, 159,160-1 

nerves, 121,126-7,161 

root, 131 
spine, 158-9 

ofscapula, 91 
splanchnic nerves, 24,25 
spleen, 46—7,53 
splenectomy, 47 
splenic 

artery, 31, 33 

lymphoid follicles, 47 

pedicles, 47 
spring ligament, 1 1 7 
squamous carcinomas, oesophagus, 1 1 
squamous temporal. 123 
stapes, 157 

stellate ganglion, 121.141 
stent insertion, 95 
sternal angle, 27 
sternebrae, 7 
sternoclavicular 

joint, 62,74,75 

ligaments, 62 
sternocleidomastoid, 1 67 
sternocostal joint, 7 
sternohyoid muscle, 142 
sternomastoid, 137, 157 
sternothyro id, 1 42 
sternum, 7 
steroid hormones. 49 
stomach, 38, 39 

lymphatic drainage, 35 
straight sinus, 135 
strap muscles, 131, 142 
striate arteries, 133 
styloglossus muscle, 147 
stylohyoid ligament, 139 
styloid process, 91.93 
stylomastoid foramen, 124 
subacromial bursa, 79 
subarachnoid space. 152, 155. 160 
subclavian 

artery, 7,13,91,7.^4,135,140,141,157 

vein, 13.135, 141 
subcostal 

artery, 13 

muscle, 9 

nerve, 51 

plane, 53 
subdural haemorrhage. 133 
sublingual 

gland, 121,145 

papilla. 145 
submandibular 

duct, 145 

ganglion, 121, 145 

gland, 121,145 

lymph nodes, 157 

region, 144-5 
submental lymph nodes. 157 
subsartorial canal, 95,707,108 
subsartorial plexus, 108 
subscapular 

artery, 67 

bursa, 79 
subscapularis, 75.79.163 
subtalar joint, 115 
sulcus terminalis, 147 
superficial 

cervical artery, 135 

cervical ganglion, 155 

circumflex iliac artery, 107 

epigastric artery, 107 

external pudendal artery, 107 

inguinal lymph nodes, 119 



174 Index 



inguinal ring, 53,162 

palmar arch, 67,91 

palmar branch (radial artery), 67 

perineal pouch, 59 

peroneal nerve. 101,113 

radial nerve. 71, 85 

temporal artery, 133, 149, 157 

transverse perineal muscles, 59 
superior 

angle of scapula, 91 

cardiac branch. 131 

cerebellar artery, 135 

cervical ganglion, 121 

constrictor muscle, 139, 145, 146 

extensor retinaculum, 1 1 3 

flexor muscles, 1 13 

gluteal artery, 57,95,105 

gluteal nerve, 101, 1 05 

hypogastric plexus, 51 

labial branch, 133 

laryngeal nerve, 131 

mediastinum, 1 1 

mesenteric artery, 31 , 33 

oblique muscle, 155 

ophthalmic vein, 1 55 

orbital fissure, 123. 127, 129. 154, 155 

parathyroid gland, 143 

peroneal retinaculum , 113 

petrosal sinus, 135 

radio-ulnar joint, 52,83 

rectal artery, i2, 33 

rectus muscle, 155 

sagittal sinus, 135,752,153 

thoracic artery, 135 

thyroid artery, 133,142 

thyroid vein, 135, 142 

tibiofibular joint, 93,113 

ulnar collateral branch. 67 

vena cava, 13 

vesical artery, 57 
supination, mechanism, 64 
supinator. 83, 164 
supraclavicular nerves, 127,137 
supracondylar lines, 93 
suprahyoid muscles, 145 
supraorbital 

foramen, 125 

nerve, 129, 157 
suprapatellar bursa, 1 1 
suprarenal 

glands, 49 

medulla, 121 
suprascapular 

artery, 135 

nerve, 73 

vein, 135 
supraspinatus, 75,79,163 
supraspinous ligaments, 159 
suprasternal notch, 27 
supratrochlear 

lymph nodes, 69 

nerve, 129 
supravaginal cervix, 61 
sural 

artery, 95 

communicating branch, 101 

nerve, 101 
suspensory ligaments 

of axilla, 69,75 

of eye, 155 

ofTreitz, 39 
sustentaculum tali, 115,119 
sutures, 123 

sympathectomy, upper limb, 25 
sympathetic 

nervous system, 50,51,720,121, 
155 

outflow, 121 

trunk, 121,141 
symphysis pubis, 53,55 
synapses, 121 
synovial 

ball and socket joints, 79,102 

flexor sheaths, 89 



hinge joints, 83, 115, 145 
modified, 110 

membrane, 19,110 
synovium, 103 
synthetic grafts, 95 

talocalcaneal 

joint. 115 

ligament, 117 
talocalcaneonavicular joint, 1 15 
talus, 7i4, 115, 119 
tarsal 

bones, 115 

glands, 150 

joints, 115 

plates, 150 
taste fibres, 145 
teeth. 147 

tegmen tympani, 157 
temporal 

bone, 123, 124 

tympanic plate, 1 24 

nerve, 131 
temporalis, 145,148,161 
temporomandibular joint, 144,145 
tendo calcaneus, 113,115.119 
tendons, wrist, 90 
teniae coli, 42,43 
tensor 

fasciae latae, 105.165 

palati muscle, 146 
tentorium cerebelli, 152, 153 
teres 

major, 75,79, 163 
inferior border, 67 

minor, 71,75,79,163 
testicular artery, 59 
testis, 55,59 

lymphatic drainage, 35 
thenar muscles, 88, S9 
thigh, 106-8 
thoracic 

aorta, 12, 13 

cage, 6, 1 

duct, 70.11.69,135,740,141,142 

inlet, 6,1 

outlet, 6, 140 
syndrome, 140 

spine, 159 

sympathetic trunk, 25 

vertebrae, 755, 159 

wan, 6-9 
thoracoacromial artery, 67,75 
thoracodorsal nerve, 73 

injuries, 77 
thorax 

lines of orientation. 27 

nerves, 24-5 

surface anatomy, 26-7 

vessels, 12—13 
thumb, movements, 89 
thymus gland. 1 1 

development, 143 
thyroarytenoid muscle, 139 
thyrocervical trunk, 13, 135, 141 
thyroglossal 

cysts, 143, 157 

duct, 143,147 
thyrohyoid 

ligament, 139 

muscle, 142 
thyroid 

cartilage, 139,157 

gland, 142-3,157 
thyroidea ima artery, 1 3 
tibia, 92,93,110,114,119 
tibial 

condyles, 93, 119 

nerve, 95,700, 101,111, 113,119 

plateau, 93 

tuberosity, 93, 119 
tibialis 

anterior, 113,115,119,166 

posterior, 113.115,119,166 



toes, 95 

tongue, 143,144,146 

lymph drainage, 157 
tonsil, 147 
tonsillar 

branch of facial artery, 133, 147 

fossa, 146 
tonsillectomy, 147 
trachea, 14, 15, 137, 142, 157 

surface markings, 27 
tracheo-oesophageal fistula, 142 
transpyloric plane (of Addison). 53 
transtubercular plane, 53 
transverse 

acetabular ligament, 102 

arch, 117 

cervical nerve, 137 

cervical vein, 135 

ligament, 755 

process. 159 

anterior tubercles, 755 

sinuses, 153 
transversus 

abdominis, 25,30, 162 

thoracis, 9 
trapezius, 75,137,162,167 
trapezoid 

ligament, 62 

line, 62 
triangular 

ligaments, 36, 37 

space, 74,15 
triceps, 71,81,83, 163 
tricuspid valves, 20,21 
trigeminal 

ganglion, 129 

nerve, 128-9, 149 

mandibular division, 145 
trigone. 61 
trochanteric 

anastomosis, 95 

crest, 93, 102 

line, 93,102 
trochlea, 63 
trochlear 

nerve, 726,127,155 

notch of ulna, 63 
true 

pelvis, 55 

ribs, 7 
trunks, 35 
tumours 

intestinal, 45 

oesophagus, 1 1 

parotid gland, 149 

vocal cords, 139 
tunica 

albuginea, 59,61 

vaginalis. 59 
tympanic membrane, 756,157 

ulna, 64,91 

olecranon process, 91 
ulnar 

artery, 67,85.91 

collateral ligament, 87 

head, 64 

nerve, 63,72,73,81,55,91 
umbilical artery, 57 
uncinate process, 47 
upper 

deep cervical lymph nodes. 157 

gastrointestinal tract, 38-41 

subscapular nerve, 73 

ureter, 49 
upper limb 

arm. 80-1 

arteries, 66-7 

bones, 91 

joints, 91 

lymphatic drainage, 68-9 

lymphoedema, 69 

muscles, 74,75. 162-4 

nerves, 70-3.91 



Index 175 



upper limb [cont.) 

osteology, 62-5 

soft tissues, 91 

surface anatomy, 90-1 

venous drainage. 68-9 

vessels, 91 
urachus, 60 
ureter, 49,60 
ureteric 

colic, 49 

stones, 49 
urethra, 59,61 
urethral 

crest. 61 

sphincter, 59 
urogenital region, 59 
uterine artery, 57,60 
utero-sacral ligaments, 57 
uterus, 56, 60, 61 
utricle, 157 

vagina, 59, 60, 61 
vaginal 

artery, 57.59 

branch of uterine artery, 59 

cervix, 61 

fornices, 59 



vagusnerve, 121, ;.?0, 131, 141, 145 
vallate papilla, 147 
valves of Houston, 43 
varicose veins, 97 

high saphenous ligation, 96 
vas (ductus) deferens, 57.61 
vastus medialis, 108, 165 
vault (skull). 123 
veins, 134-5 

abdomen, 34-5 

abdominal wall, 29, 30 

neck. 141 

pelvis, 57 
venous 

plexus, 113 

sinuses, 134, 135, 152 
vertebrae, 91,755 
vertebral 

arteries, 13,752,135,141,161 

bodies, 159 

canal, 159 

vein, 135 
verumontanum, 61 
vestibular 

folds, 139 

nerve, 131 
vestibule, 59, 157 



vestibulocochlear nerve, 131, 157 

vitreous humour, 1 55 

vocal 

cords, 755,139 
tumours, 139 

ligaments, 138, 139 
Volkman's ischaemic contracture, 67 
vomer, 125 
vulva, 59 

weakened arm abduction, 77 

Wharton's duct, 145 

white pulp, 47 

white rami communicantes, 1 2 1 

wrist, 91 

injuries, 64 

joints, 86-7 

nerves, 71 

tendons, 90 

xiphisternal joint, 7,27 
xiphoid, 7 

process, 53 

zona orbicularis, 102 
zygomatic 

bone, 125 

nerve, 131, 149 



176 Index